Patent Litigation 2024 Comparisons

Last Updated February 15, 2024

Law and Practice


Kirkland & Ellis International LLP has a patent litigation practice comprised of approximately 230 attorneys in London, Austin, Boston, Chicago, Houston, Los Angeles, New York, Palo Alto, Salt Lake City, San Francisco and Washington, DC. More than 75% of Kirkland’s patent litigation attorneys are engineers and scientists, trained in a variety of technical disciplines. Kirkland’s experienced IP litigation attorneys achieve extraordinary results in patent, copyright, trade mark, trade secret misappropriation and advertising matters. They represent clients across a broad range of industries, including life sciences, technology, consumer products manufacturing, financial services, automotive, and food and beverage. Other areas of practice are pharmaceutical and biologics patent litigation, co-ordinating global IP enforcement/defence cases, SEPs and FRAND disputes, post-grant proceedings before the US Patent and Trademark Office’s Patent Trial and Appeal Board, and appeals of high-stakes cases in the US Court of Appeals for the Federal Circuit and the US Supreme Court, as well as the Court of Appeal of England and Wales and the UK Supreme Court.

Under UK law, inventions are protected through patents. There is no protection granted by way of design patents, and registered design rights must not be to protect a feature which is purely technical in nature.

The legal protection from patents is primarily governed by statute (the Patents Act 1977) but the statute is interpreted by judges, such that the case law will inform the likelihood of an invention being afforded protection.

To obtain a patent in the UK, an applicant may complete the relevant paperwork and formalities (including filing the claims, description and full text of the patent) and apply directly to the UK Intellectual Property Office (the “UK IPO”). As the UK is a member of the European Patent Convention (EPC), a prospective patent holder may also apply to the European Patent Office (EPO) for the grant of a European Patent designating the UK amongst the states in which the European Patent should grant. Later, once that European Patent has granted, the patentee should apply to the UK IPO and complete the formal registration step. Patentees should note that applications filed with the EPO in English must also be translated into French and German.

It is also possible to first file an international patent application (PCT) via the UK IPO, which will be provided to the World Intellectual Property Organisation (WIPO) for processing. The EPO is involved in the granting of a PCT, acting in the capacity of an International Search Authority. Following publication of the application, the prospective patentee must then apply in the jurisdictions in which it would like the patent to be considered for grant and ultimately effective.   

The timeline to grant varies. Patents filed with the EPO typically take four years or more to be granted. Applicants may request an accelerated examination in the EPO, which is subject to the EPO’s discretion and may only be accepted where practically feasible. Patents filed with the UK IPO can take between two-and-a-half and four-and-a-half years to be granted, although the time to grant can be significantly less. Any third-party observations made during the course of the grant procedure will inevitably delay grant as the Patent Office will consider these objections.

In most cases, representation is not required, but given the specialised nature of drafting a patent application, in most instances patent agents are used. If the applicant has neither residence nor their principal place of business in an EPO contracting state, the applicant must appoint a representative.

Costs to grant vary across the types of intellectual property rights and will of course depend on any representation retained. A rough estimate for the filing of a patent application is between GBP4,000–GBP7,500. UK IPO costs of filing a patent roughly total GBP310 (depending on the number of claims and length of the patent). 

The term of a patent is 20 years from the filing date. The term can be extended for up to an additional five years by Supplementary Protection Certificates (SPCs) (see 1.6 Further Protection After Lapse of the Maximum Term).

In order to enjoy the full 20 years of protection, the owner must pay a renewal fee annually from the fourth anniversary of the filing date onwards (at the UK IPO) or the third anniversary onwards at the EPO. 

Subject to a patent being found valid and infringed, the owner will be entitled to the following remedies (as set out in more detail at 6.1 Remedies for the Patentee);

  • an injunction to prevent further infringement of the patent;
  • delivery up of infringing goods;
  • destruction of infringing goods;
  • publication of the judgment finding infringement at the cost of the infringer;
  • reasonable legal fees; and
  • damages or account of profits.

In order to maintain their rights, owners must ensure they pay any applicable renewal fees and requirements following grant.

Registered rights may be identified via the relevant registers – eg, UK patent rights can be found via Ipsum, and European patents via the EPO or Espacenet. There is no register listing patents applicable to certain products or processes.

In addition to the basic 20-year patent term, for certain medicinal products, SPCs may extend the term of protection for up to a further five years. The SPC duration can be calculated as the period that elapsed between the date on which the application for a basic patent was lodged and the date of the first MA, minus a period of five years.

SPCs were first introduced through EU regulations and subsequently imported directly into UK law following Brexit (Section 128B and Schedule 4A, Patents Act). Products protected by SPCs must first be protected by a patent in force and be subject to an active Marketing Authorisation.

Additionally, where studies have been conducted into the effects of the medicinal product in children, the patentee can apply for a further six-month paediatric extension to the duration of the SPC.

During the procedure of registering a UK patent, third parties may intervene by filing oppositions or observations. During examination of a patent, third parties may file observations with the patent office (UK IPO, EPO or WIPO as applicable) or UK IPO respectively. Following grant, it is further possible to file oppositions within a certain timeframe. The objections should be filed within nine months of grant at the EPO.

It is not possible to file an opposition to a patent registered with the UK IPO, but an opinion may be requested. The UK IPO’s senior examiners will review the patent and publish a non-binding opinion typically within three months. Following publication of an opinion that considers the patent to be invalid, the UK IPO may also decide to revoke the patent.

During the examination of a UK patent, opinions as to the registrability of the right are issued by the IPO and applicants are afforded the opportunity to rectify deficiencies. If the applications are still refused, it is possible to appeal the initial decision directly within the UK IPO. From the examiners at the UK IPO there exists the right for the applicant to appeal to the High Court – indeed, the recent case of Thaler v Comptroller of Patents was appealed all the way to the Supreme Court.

In the case of patents filed with the EPO, decisions of the Examination Division can be appealed to the Technical Board of Appeal.

There is a six-month grace period at the UK IPO in which late payment of the annual renewal fee may be paid (additional late payment fees also apply). After this period, the patent right lapses. However, if the patentee has a good reason as to why the deadline was missed, the patentee may apply to restore the patent within 13 months of expiry of the grace period.

A UK patent may be amended post-grant in certain restricted aspects (the most important consideration in a post-grant amendment context will typically be whether the amendment adds matter over and above the patent as granted). The patent may not be amended to extend the scope of its protection. The patentee may apply to the IPO or court to request amendment (in the case of the latter, the IPO should also be informed and sent the application). Patentees should note that applications to amend will be published and third parties may oppose prior to the relevant authority issuing its decision.

A claim may be brought by the owner (or an exclusive licensee) of a patent in the first-instance courts (see 2.3 Courts With Jurisdiction). Alternative dispute resolution is encouraged by the courts but is not mandatory. Most large-scale patent cases proceed to be heard before the court through to final judgment. 

Opposition proceedings cannot be brought in the UK, however, it is common to file nullity proceedings in the UK while there are parallel EPO opposition proceedings ongoing. Post-grant review is not available.

Any party can initiate an action for the revocation of a patent, and standing does not need to be established. A revocation action may be brought either before the courts of England and Wales or before the UK IPO. Infringement and validity opinions may also be sought from the UK IPO but are non-binding, however, a patent may be revoked if it is found to be invalid in a UK IPO.

A declaration of non-infringement may be granted by the Patents Court and the Intellectual Property Enterprise Court (IPEC) in main proceedings, or upon application to the Comptroller. “Arrow” declarations (ie, declarations that a claimant’s process or product was obvious or not novel) can be sought by a third party to guard against future infringement proceedings for patents granted at a later date. Arrow declarations are available in England and Wales and can be granted where “they will serve a useful purpose”.

The Patents Court, which is a division of the High Court of England and Wales, hears most patents cases, while less complex patent cases may be heard in the IPEC. Appeals from the Patents Court are to the Court of Appeal, and further appeals to the Supreme Court.

In addition to the courts, a revocation action may be brought before the UK IPO.

A main action for patent infringement can be filed at any time once a national UK patent has granted (and in certain circumstances before a patent has granted if examination at the EPO has concluded but formal grant has not yet taken place). Formal demand or warning letters are not a prerequisite for filing a claim, nor is engaging in mediation.

Although parties are not required to be represented by a lawyer, it is uncommon that they not be.

Preliminary injunctions (PIs) are available in the UK as an interim equitable remedy, and the court grants them where there is a serious issue to be tried and the balance of convenience favours the grant of the PI. PIs can be applied for on an ex parte basis if appropriate. It is more common for an application for a PI to be issued inter partes within the context of main proceedings commenced in parallel. Patent validity is not assumed in PI proceedings and the alleged infringer has the opportunity to introduce evidence to the contrary in the PI proceedings.

The timing and length of PI proceedings depend largely on facts and are based on commercial urgency. As a discretionary equitable remedy, courts expect that a party seeking a PI will do so expeditiously – the failure of an applicant to act with sufficient urgency in all of the circumstances is likely to count as a factor against the grant of the PI sought. The court will consider the factors from American Cyanamid.

  • Is there a serious issue to be tried? The claim must not be frivolous or vexatious.
  • Whether damages would be an adequate remedy. This is assessed from the claimant’s perspective and important factors here include the difficulty of ultimately assessing loss (ie, would there be an unpredictable price spiral in a pharmaceutical market if a generic was allowed onto the market) and the financial positions of the parties.
  • Where does the balance of convenience lie? This is a multifactorial assessment based on likely outcomes for both parties.
  • Any other special factors.

When obtaining a PI, the claimant must provide a cross-undertaking to compensate the alleged infringer for damages in the event the injunction was found to have been unjustified. The undertaking remains in place until a final order is made following the first-instance action and any appeal.

In pharmaceutical or medical device patent cases, if an interim injunction affects dealings with the National Health Service (NHS), the patentee may be required to provide cross-undertakings in damages in favour of the NHS and they would also be entitled to damages if the patentee is unsuccessful.

Protective letters are not available in England and Wales.

The limitation period for bringing a claim for patent infringement is six years from the date the cause of action accrued (under Section 2, Limitation Act 1980).

Pre-action disclosure is not available as of right. Orders for pre-action disclosure can be sought if the would-be claimant can demonstrate that this may settle the dispute without the need for proceedings. The court can also order a third party to disclose documents to an applicant before proceedings have started in order to enable the applicant to commence proceedings against the appropriate party.

Disclosure in the main proceedings in patent cases is most common in relation to the issue of infringement rather than validity. Disclosure by an alleged infringer on the issue of infringement is commonly provided by way of a Product and Process Description (PPD), which is a self-contained document, provided in lieu of the relevant underlying documents, and sets out sufficient information for the court to determine whether or not the patent has been infringed.

Disclosure in the main proceedings follows the provision of an “Initial Disclosure List”, which is provided by the parties when they provide their initial pleadings and sets out the documents upon which they rely. Significantly, there is no requirement to disclose documents that adversely affect a party’s case as part of the Initial Disclosure List.

Unless ordered otherwise, use of documents obtained in disclosure is restricted to the English proceedings and cannot be used in other jurisdictions.

Search and seizure orders are available as a form of interim mandatory injunction and applications are made ex parte but these are not a regular feature of patent litigation in England and Wales.

To start an action, a claimant must prepare a claim form, particulars of claim and – depending upon whether the claim relates to patent infringement or revocation – either a particulars of infringement or grounds of invalidity. For high-value claims before the Patents Court, the particulars are high-level at this early stage. This is also the case for the defendant’s response in its defence and any counterclaim, with detailed information following when the timetable to trial is set, particularly at the disclosure/discovery and expert evidence stages. Amendments to the pleaded case are permissible with the agreement of the opposing party or the court. The possibility of amending the case in a significant fashion becomes less likely as the case nears trial, owing to the greater potential prejudice to the opposing party.

As standing is not required to initiate revocation proceedings, such proceedings could theoretically be brought as collective actions, however, this has not happened.

It is an actionable offence for a patent proprietor to threaten to sue for patent infringement against a suspected or potential infringer when the threat is unjustified (Section 70A Patents Act). However, there are otherwise no restrictions on the owner of an intellectual property right asserting its rights against others. If a defendant believes they are being sued baselessly, they have an option to apply for summary judgment in the early stages of the case.

Many telecommunications patents are encumbered by declarations to the European Telecommunications Standards Institute (ETSI), which contains a contractual derogation of the automatic right to seek an injunction for patent infringement.

Only the proprietor(s) of the patent or an exclusive licensee can bring an action for patent infringement. Note that:

  • where there are multiple proprietors, a single co-owner may bring infringement proceedings but the other owner(s) must be joined to the proceedings – either as a co-claimant or, if they do not wish to take part in the action, as a non-participating defendant; and
  • similarly, exclusive licensees can also bring an action on their own but the proprietor of the patent must be joined as a co-claimant or defendant. An exclusive licensee’s right to bring proceedings is limited to the rights that have been licensed. Exclusive licensees should ensure their licence is registered (for the reasons set out at 10.3 Requirements or Restrictions to License an Intellectual Property Right).

English law draws a distinction between acts of direct patent infringement and indirect patent infringement.

  • Direct infringement encompasses in relation to (i) product claims: acts of making, disposing of, offering to dispose of, using or importing the product, (see Section 60(1)(a)); and (ii) process claims (as set out further in 3.3 Process Patents).
  • Indirect infringement is subject to a knowledge requirement and a “double territoriality” requirement. The question is whether a person supplies or offers to supply in the United Kingdom the means, “relating to an essential element of the invention”, for putting the invention into effect knowing (or it is obvious to a reasonable person in the circumstances), that those means are suitable for putting, and are intended to put, the invention into effect in the United Kingdom (see Section 60(2)).

There is distinction between the remedies available for direct or indirect infringement. The remedies for patent infringement are set out in 6.1 Remedies for the Patentee.

A different test for infringement applies for process claims under English law compared to product claims.

  • Acts of using or offering a patented process for use must take place in the United Kingdom and is subject to a knowledge requirement that does not apply to product claims (see Section 60(1)(b)).
  • There is a separate provision that renders infringing the act of disposing, or offering to dispose of, using or importing any product obtained directly by means of a patented process (see Section 60(1)(c)). Since there is no restriction on where the process is carried out, it can be useful in cases where the infringing process is practised outside the United Kingdom so long as the products are dealt with in the jurisdiction.

English Courts adopt a “purposive” approach to construing patent claims to determine the scope of the claims. In particular, the English Court will consider the words of the claim as understood by a skilled person in context of the patent (Catnic Components Ltd v Hill & Smith Ltd [1982] RPC 183 (HL)). A patent’s prosecution history will ordinarily not be considered except in exceptional circumstances.

More recently, the UK Supreme Court in Actavis UK Ltd and others v Eli Lilly ([2017] UKSC 48), have developed and applied a “doctrine of equivalents” in infringement claims by applying a three-step test to determine whether there is infringement by an “immaterial” variant.

  • Does the variant achieve substantially the same result in substantially the same way as the invention – ie, the inventive concept revealed by the patent?
  • Would it be obvious to a person skilled in the art, who reads the patent at the priority date but knows that the variant achieves substantially the same result as the invention, that the variant does so in substantially the same way as the invention?
  • Would such a reader of the patent have concluded that the patentee nonetheless intended that strict compliance with the literal meaning of the relevant claim(s) of the patent was an essential requirement of the invention?

In order to establish infringement by equivalents, a patentee would have to establish that the answer to the first two questions was “yes”, and “no” to the third.

Other than non-infringement arguments, there are a wide range of defences to an infringement claim under English law, including the following.

Statutory Defences

  • Innocent infringement (see Section 62(1)).
  • Prior use (see Section 64).
  • Crown use (see Section 55).
  • Supply of staple commercial products (see Section 60(3)).
  • Private acts done for non-commercial purposes (see Section 60(5)(a)).
  • Acts done for experimental purposes, and for certain studies, tests or trials (the “Bolar” exemption) (see Section 60(5)(b)).

Other Defences

  • Counterclaims for invalidity as you cannot infringe an invalid patent. These are dealt with alongside the infringement claim.
  • The “Gillette” defence, where the alleged infringer argues the infringing product implements the prior art (so that if the product infringes, the patent must be invalid).
  • In the context of equivalents, the courts have applied the “Formstein” defence (which has origins in German law) where the alleged infringer argues the equivalent is not patentable.
  • Consent, repair and/or exhaustion.
  • “FRAND” defence for infringement of standard essential patents. Here, the English courts have shown willingness to determine the terms of a FRAND licence covering the patents rather than enforce an injunction.

Expert evidence on issues of patent infringement and validity is key in English patent litigation and can only be adduced with the permission of the court. Ordinarily, each party calls their own expert witness(es) (though the court may direct that evidence should be given by a single joint expert, which is rare).

The overriding duty of an expert witness is to assist the court on matters within their expertise and they must remain impartial. In cases with more than one expert on each side, the court may consider experts should have the opportunity to discuss their views with the other experts on the same side as they would have in the hypothetical skilled team. It is rare for the court to appoint an expert, but it is possible. Scientific advisers may be appointed by the court; however, this is also rare.

The claims of a patent are construed as part of the infringement action (alongside any counterclaim for invalidity). Procedurally, once the parties to the action file their initial claims, defences and/or counterclaims, the court will make orders requiring the parties to file more detailed “Statements of Case” which will address matters of claim construction on infringement and invalidity. The key to claim construction issues in English litigation will usually be the reports of the expert witnesses. 

The English court does not usually, of its own motion, seek or receive third-party opinions in a patent infringement or invalidity action (see also 3.6 Role of Experts).

Revocation of a patent can be sought before the UK IPO or the courts. A claim for revocation can be made pre-emptively in order to clear the way and obtain freedom to operate or can be raised as a counterclaim to infringement proceedings.

A party seeking revocation of a patent will seek, by way of remedy, an order of the court for the unconditional revocation of the patent and may also seek a declaration by the court that the patent is invalid. Revocation of a patent by the court or the UK IPO has effect ab initio – ie, the patent is treated as if it had never been granted.

There are no formal standing requirements in respect of a revocation action – any person can apply to revoke a patent, regardless of intention and even in the absence of any commercial interest in the revocation of that patent.

The court or the UK IPO may revoke a patent on any of the following grounds, set out in Section 72(1) of the Patents Act 1977 and derived from Article 138 EPC.

  • The invention is not patentable – ie, a patent may be revoked if it is not novel, is obvious or it is not capable of industrial application or if it concerns excluded subject matter.
  • The patent was granted to a person who was not entitled to be granted the patent.
  • The specification of the patent does not disclose the invention clearly and completely enough for it to be performed by a person skilled in the art. This ground is often referred to as insufficiency.
  • The matter disclosed in the specification of the patent extends beyond that disclosed in the application as filed – this ground is often referred to as added matter.
  • The protection conferred by the patent has been extended by an amendment that should not have been allowed.

Partial revocation is possible – ie, some of the claims of the patent might be found to be valid and others might be found to be invalid.

A patent owner can apply in writing to the UK IPO to amend their patent, identifying the proposed amendment and stating the grounds on which the amendment is made; following which the UK IPO may grant the amendment with any conditions that it sees fit. If there are pending proceedings before the Court or the UK IPO, in which proceedings the validity of the patent might be put in issue, amendment is not permitted as of right.

Conditional amendments (ie, in the event that the claims as granted would otherwise be found invalid) are permitted in England and Wales, and when making an application to amend, the patent owner must state whether or not it will contend that the original, un-amended claims are valid.

Applications to amend must be served on the other parties to the litigation as well as on the Comptroller General of Patents, Trade Marks and Designs at the UK IPO and the application must be advertised in the UK IPO’s patents journal (unless the court orders otherwise), as amendments sought by the patent owner during proceedings before the court or the UK IPO may be opposed by any person (whether or not a party to the proceedings).

If an application to amend is made to the court, the UK IPO will prepare a report for the benefit of the court as to whether it considers the amendments to be allowable. The court or the UK IPO has discretion as to whether to allow an amendment sought in revocation proceedings but must take into account relevant principles under the EPC. 

Any amendment of a patent is effective as if it were made from the date of grant of the patent.

Post-trial amendments aimed at setting up a new claim to save a claim found invalid at trial are likely to be refused if a new trial on the validity of the proposed new claims would be required.

There is no bifurcation in England and Wales. Issues of infringement and validity are dealt with in the same proceedings and at the same trial, and decisions in respect of infringement and validity are handed down at the same time as part of the same judgment.

Typical Timeline of Patent Infringement Proceedings

In intellectual property rights proceedings, patent litigation proceedings in England and Wales follow a relatively structured timeline prescribed by the Civil Procedure Rules and the Patents Court guide. The Patents Court endeavours to bring all patent cases on for trial within 12 months of the claim being issued (not including cases being expedited or streamlined by other means such as the shorter trial scheme) (see the Chancellor of the High Court’s Practice Statement dated 1 February 2022).

The typical timeline of patent litigation proceedings involves several key procedural steps.

  • Issue of proceedings – commencement of the proceedings by filing the necessary documents to initiate the case.
  • Acknowledgment of service – the defendant’s formal acknowledgment of the proceedings. This step is taken 14 days after service of the claim. Whilst this step is not required, it is typically taken as it allows additional time for service of the defence. The following deadlines assume an acknowledgement of service has been filed.
  • Defence and counterclaim – presentation of the defendant’s response and any counterclaims they may have. Under CPR 63.6 this shall occur within 42 days of service of the Claim and an Acknowledgement of Service being filed.
  • Reply and defence to counterclaim – the claimant’s response to the defence and any counterclaims, along with their own counterarguments, which shall occur within 21 days of the service of the defence and counterclaim.
  • Case management conference – a pivotal stage where directions to trial are set, encompassing aspects such as disclosure, fact and expert evidence, and experiments.
  • Experiments – providing notice of, and conducting any necessary experiments as part of the evidentiary process.
  • Fact and expert evidence – gathering and presenting both fact and expert evidence, with the number and scope of witnesses determined at the case management conference or through mutual agreement.
  • Trial – the culmination of proceedings, where issues of both infringement and validity are typically addressed in a single trial hearing. Multiple trials may occur if multiple patents are asserted, each requiring a separate trial.

The Trial

In patent litigation proceedings in England and Wales, there is typically only a single trial hearing to determine issues of both infringement and validity. However, multiple trials may occur if a claimant asserts more than one patent, necessitating separate trials for each patent.


Parties in patent litigation may rely on both fact and expert evidence. The case management conference determines the number of witnesses and the timeline and scope of their evidence, unless agreed otherwise. The type and number of witnesses depend on the nature and complexity of the proceedings. Fact witnesses provide evidence in chief through witness statements, and experts present their evidence through expert reports, signed by a statement of truth. Witnesses are called to testify at trial, and they undergo cross-examination by the opposing party. Unlike some jurisdictions, there is no direct examination in patent litigation proceedings in England and Wales; the written evidence serves that purpose.

Judgment and Remedies

Whilst damages for infringement are often dealt with at trial, complex matters may lead to a separate damages hearing. After the trial, the judge typically reserves judgment for a later date, which may take several months. Subsequently, the parties attend a final order hearing to determine the form of the final order and address any remaining issues, such as costs. In cases where costs cannot be agreed upon, a detailed assessment hearing is convened to determine the matter of costs.

The Decision-Makers in Patent Litigation Proceedings in England and Wales

In the context of civil proceedings in England and Wales, the determination of cases relies on the expertise of judges rather than a jury. Not all judges within the Patents Court have technical intellectual property backgrounds, however, a number of them do. Usually, cases involving more complex technical issues (in terms of the patent, the prior art as well as the infringement issues and likely evidence) will be heard by a suitably qualified Patents Court Judge (Patents Court Guide, paragraph 3). Notwithstanding that, it is pertinent to note that interim hearings in complex technical patent cases might still be presided over by non-technical Patents Court Judges.

Parties involved in patent litigation proceedings do not exert influence over the selection of judges. The assignment typically depends on the availability of the court and judges, taking into consideration any existing conflicts that might impact their impartiality.

The avenues for parties to resolve proceedings are largely focused on encouraging amicable resolutions through negotiations and alternative dispute resolution (ADR) mechanisms. ADR is discussed further at 9.1 Type of Actions for Intellectual Property. Noteworthy is the court’s power to mandate parties to engage in ADR, with recent pronouncements from the Court of Appeal (in Churchill v Merthyr Tydfil County Borough Council [2023] EWCA Civ 1416) affirming the court’s ability to order parties to participate in “non-court-based dispute resolution”. This underscores the judiciary’s commitment to facilitating settlements through proactive measures.

In addition to the voluntary nature of negotiations and ADR, the legal framework in England and Wales has certain mechanisms designed to incentivise parties to reach a settlement. Notably, “Part 36” and “Calderbank” offers are tools that offer cost incentives to encourage the parties to consider settlement seriously. The Civil Procedure Rules, Part 36 procedure stands out as a beneficial mechanism (in particular for claimants), providing a structured framework that offers advantageous cost consequences. This procedure, tailored to expedite settlements, can be a useful tool in patent litigation proceedings.

The case can be settled by an Order agreed between the parties and sealed by the court. Often a “Tomlin” Order is used if there are confidential settlement terms.

The interplay with other court proceedings such as parallel revocation/infringement actions and the issuance of anti-suit injunctions, can significantly impact the course of proceedings.

Parallel Revocation/Infringement Proceedings

The court may consider staying infringement proceedings pending the resolution of a parallel revocation action in another forum, including in the European Patent Office, however, it is not a requirement and often cases are not stayed in light of parallel proceedings (eg, Neurim and Anor v Generics (UK) Ltd and Anor [2021] EWHC 2897 (Pat)).

Anti-Suit Injunctions

Whilst foreign anti-suit injunctions are not automatically binding on the courts in England and Wales, their existence may prompt a careful examination of jurisdictional issues and fairness within the ongoing proceedings in England and Wales. The courts will assess the relevance and validity of such injunctions, taking into consideration their potential impact on the current litigation in determining whether or not to enforce them.

Influence on Current Proceedings

The influence of parallel actions and anti-suit injunctions in patent litigation in England and Wales depends on the specific circumstances of each case. Courts strive to balance efficiency in dispute resolution with the principles of fairness, in furtherance of the overriding objective.

The remedies that a patentee may seek and that may be granted on a finding of patent infringement (pursuant to Section 61 of the Patents Act 1977) include: injunction (preliminary injunctive relief and final injunctive relief); damages or an account of profits; order for delivery up and destruction; relief for infringement of partially valid patent; certificate of contested validity; and costs.


Injunctions are discretionary in England. The factors relevant to the exercise of that discretion in a preliminary injunction context are addressed at 2.7 Interim Injunctions. Patents provide exclusionary rights and if a patent is shown to be valid and infringed, the court will typically grant a final injunction (the effect of which might be stayed pending any appeals). However, as injunctions are discretionary, the court will consider if an injunction is the appropriate remedy or whether, for example, a licence would be more appropriate.

Damages or Account of Profits

A successful claimant is entitled to elect for damages or an account of profits, but not both. A court may use its discretion to award damages instead of an injunction. In taking into account damages, a successful claimant should be put in the same position as they would have been if the infringement had not occurred, provided that the claimant proves its losses are foreseeable, caused by the wrong, and not excluded from recovery by public or social policy (see Gerber v Lectra [1997] R.P.C. 443 at 452  and Lord Wilberforce in General Tire & Rubber Co v Firestone Tyre & Rubber Co Ltd [1976] R.P.C. 197 at 212). Damages are recoverable from the date of publication of the application. Exemplary damages are available in certain circumstances (such as where the infringement is oppressive, arbitrary or unconstitutional). The court must also consider any unfair profits made by the infringer where they have infringed with knowledge (pursuant to Article 13 of the IP Enforcement Directive Regulations 2006, which has been implemented in the UK by Article 3 of the Intellectual Property (Enforcement, etc) Regulations 2006). Interest may be awarded on all sums payable, from the date of each infringement complained of.

An account of profits is supposed to deprive the defendant of the profits that they have made improperly by way of infringement, and transfer any of that benefit to the claimant. There may be a need for apportionment of the profits if only part of a product or process infringes. The quantum of damages or account of profits is decided in a separate hearing following the main infringement proceedings. Given the time and evidence involved in damages inquiries, the parties often reach a settlement prior to the quantum trial.

Order for Delivery Up or Destruction

Pursuant to Section 67(1)(b) of the Patents Act 1977, the patentee who successfully sues for infringement can obtain an order for the destruction or delivery up of infringing goods in the possession of the defendant. This usually includes goods in the UK and in the defendant’s custody, power or control on the day that the order is made. The infringing party may be ordered to confirm that it has done so and/or what steps it has taken to comply, and will be ordered to give disclosure as to any infringing goods in their possession or power. An order for delivery up and destruction may be stayed pending appeal. 

Relief for Infringement of Partially Valid Patent

If a patent is found to only be partially valid, a patentee may still obtain relief in respect of the valid parts of the patent, including damages and an account of profits (pursuant to Section 63(1) of the Patents Act 1977).

Certificate of Contested Validity

The patentee is entitled to a certificate of contested validity where they have successfully defeated a claim of invalidity. At the court’s discretion, this can carry costs implications for future challenges to the patent.


The successful party may also be entitled to recover their costs (or a proportion of their costs), from when the action is filed (including court fees). Costs are discussed further at 8.3 Responsibility for Paying the Costs of Litigation.

A successful defendant has the same rights as a prevailing claimant, as applicable. For instance, if the defendant is a patentee and the claimant fails to show invalidity/non-infringement then the defendant would have each of the remedies as set out at 6.1 Remedies for the Patentee.

If the defendant is not the patentee, a successful defendant in an infringement action would also be entitled to recover their costs (as referred to in 6.1 Remedies for the Patentee), either proportionate and reasonable or on an indemnity basis. Similarly, as discussed in 6.1 Remedies for the Patentee, if a defendant is successful in partly invalidating the patent, the defendant only has to pay damages or an account of profits with respect to the parts of the patent found to be valid.

If the defendant has been subject to an interim injunction they will be entitled to damages on any cross-undertaking after an interim injunction is discharged. The court will assess the damages “upon the same basis as that upon which damages for breach of contract would be assessed if the undertaking had been a contract between the plaintiff and the defendant that the plaintiff would not prevent the defendant from doing that which he was restrained from doing by the terms of the injunction” (see Smith v Day (1882) 21 Ch D. 421 per Brett LJ at p. 427).

If the defendant or its customers has been the subject of threats, there also exist remedies for groundless threats of infringement proceedings, whereby the alleged infringer can seek damages, an injunction to prevent further threats, and a declaration that the threat lacked justification.

No additional technical intellectual property rights exist in the UK.

The court has discretion as to whether or not to stay an injunction pending appeal, and it applies the balance of convenience test in exercising its discretion. For example, in the case of public inconvenience, the immediate operation of an injunction may be suspended to minimise such inconvenience, or to avoid extensive unemployment.

Where a stay is granted for an injunction pending appeal, it is generally ordered that it should be stayed for such time to enable the defendants to give notice of appeal, and to continue in force until the appeal has been pursued with due diligence. The appellant, which is subject to the stayed injunction, is required to keep a record of their accounts relating to the disputed product/process or otherwise make payments into escrow. The patentee is often given the option of whether to enforce the injunction pending appeal (subject to an appropriate cross-undertaking in damages). The court has taken the following considerations into account when deciding whether to exercise its discretion to grant a stay.

  • Whether the party seeking the stay and the appeal (if unsuccessful) will be in the same position as if they had not sought the stay, and whether the patentee that was successful at first instance would be in the same position as if the appeal was upheld and the stay had not been granted (see Kirin-Amgen Inc v Transkaryotic Therapies Inc [2005] F.S.R. 44).
  • The economic consequences to each party of the injunctive relief (HTC Corp v Nokia Corp [2013] EWHC 3778 (Pat), [2014] R.P.C. 30).
  • Whether the party requesting the stay is willing to provide financial relief (Adaptive Spectrum and Signal Alignment Inc v British Telecommunications Plc [2014] EWCA Civ 1513).

Timeline for Appeals

In patent proceedings, appeals to the Court of Appeal typically must be filed within a timeframe of 21 days after judgment is handed down. It is customary in patent proceedings for this period to be stayed pending the issuance of the final order from the first instance proceedings. This ensures that the clock for the 21-day filing period starts running from the date of the final order, allowing parties a reasonable window for lodging appeals. This is a common approach in patent proceedings and recognises the need for clarity on the final judgment before initiating the appellate process.

Rules and Alternative Procedure

Whilst patent appeals to the Court of Appeal generally follow the same rules as other appeals to the Court of Appeal, there exists a specific provision outlined in Annex G of the Patents Court Guide requiring the parties to provide time estimates and a timetable for the appeal.

Appeals to the Court of Appeal in patent proceedings are intentionally confined to questions of law. Unlike the trial stage, where facts are thoroughly examined and determined, the appellate review does not embark on a comprehensive reassessment of the factual landscape. Instead, the focus is directed towards legal issues, ensuring that the appeal is centred on the interpretation and application of legal principles relevant to the case at hand.

The appellate process does not allow a full review of the facts of the case. The Court of Appeal is not a forum for a re-evaluation of the evidence, or a reconsideration of factual determinations made at the trial level. This characteristic underscores the finality and conclusiveness of factual findings reached during the trial, promoting judicial efficiency and a focused appellate review that aligns with the overriding objective. Further, the introduction of new evidence on appeal is prohibited unless it was not available at the time of the trial.

Before filing a lawsuit, the claimant generally sends a “cease-and-desist” letter, “letter of claim” or “letter before action”, which provides a notice of infringement to the potential defendant before enforcing their intellectual property rights. The purpose of this correspondence is to provide the defendant with warning as to the claimant’s intention to file proceedings, and to invite the defendant to offer a counter-argument to a possible infringement claim.

There are costs involved in first obtaining advice from a law firm as to the prospects of success of the claim, the drafting and sending of the “cease-and-desist” letter, advice on jurisdiction and service, and the preparation and service of the documents required for the commencement of proceedings (being a claim form, particulars of claim, and either a particulars of infringement or grounds of invalidity). The costs of the advice and pre-litigation correspondence will differ from law firm to law firm, but the actual filing of the pleadings is a fixed cost set by the court (as referred to in 8.2 Calculation of Court Fees).

In the High Court, the claimant is required to pay a court fee to start proceedings, which is based on the value of the claim. If the claim is one for money (for example, a claim for damages or an account of profits), the fee payable upon issue of proceedings is 5% of the amount for claims worth between GBP10,000–GBP200,000, or GBP10,000 for claims worth more than GBP200,000. If the claim is a non-monetary claim (such as for injunctive relief), then the fee is GBP569. If the claimant is seeking both monetary and non-monetary relief, then both fees must be paid. The court fees are not dependent on how many patents or defendants there are.

Whilst the claimant is required to pay the court fees and trial fees, each party is responsible to pay its own attorney fees and expenses during the proceedings until there is a final decision.

Generally, costs follow the event and the losing party is required to reimburse the prevailing party for their costs of litigation. These costs include court fees, expenses and attorney fees. The court has a general discretion under Part 44 of the Civil Procedure Rules as to the amount of costs to be ordered, the manner in which they are paid and when they are to be paid. As stated in 6.1 Remedies for the Patentee, the court will take into account any more discrete issues on which the parties have been successful or unsuccessful, settlement offers from either party, the conduct of the parties throughout the litigation, and the reasonableness of the costs of either party.

The successful party may recover proportionate and reasonable costs (which equate to around 60%–70% of their costs) if they win on all issues raised in the litigation, or on an “indemnity basis” if the losing party has conducted itself unreasonably (which equates to around 80%–90% of their costs). In any award of indemnity costs, the court will take into account factors such as any discrete issues that the ultimate winner may have lost on, and any settlement offers from either party. The court will also take into account the conduct of either party throughout the litigation and can address unreasonable or improper conduct in its award of costs.

There is a cap of GBP500,000 on recoverable costs in the IPEC, which is a specialist list of the Chancery Division of the High Court. It was established to deal with claims of less value and which are shorter and less complex.

As mentioned in 5.3 Settling the Case, the Courts of England and Wales encourage and require parties to disputes of any kind, including intellectual property disputes, to actively engage in ADR procedures. This is a requirement in the CPR and parties need to raise the option of ADR even before the commencement of traditional legal proceedings through the courts.

Although the most common option to resolve large-scale patent disputes is through the courts, certain forms of ADR are still utilised. The most common forms of ADR used in patent disputes include arbitration and mediation. The need to arbitrate disputes is often written into patent licences, whereby related disputes should be settled through the procedure of an agreed and accredited arbitration forum. 

An assignment of a UK patent or patent application must be in writing and signed by the assignor – in practice it is usual for both parties to sign the assignment.

No approval of the UK IPO is required to effect an assignment of a patent or a patent application.

There is no requirement to register an assignment at the UK IPO. However, it is recommended to do so, as failing to register an assignment can have significant consequences.

  • Third parties can acquire interests in a patent or patent application without being bound by an earlier unregistered assignment (unless they otherwise knew of the assignment).
  • In addition, an assignee who does not register an assignment within six months of the effective date of the assignment is not able to claim costs or expenses in proceedings for infringement of that patent where that infringement took place prior to registration.

A UK patent or patent application can be assigned by contract and the assignment may or may not be registered at the UK IPO (see 10.1 Requirements or Restrictions for Assignment of Intellectual Property Rights). Registration of an assignment requires completion of Patents Form 21, with the completed form to be sent to the UK IPO. Patents Form 21 can be used for more than one patent or patent application, provided that each relates to the same assignment transaction.

If the form is signed by only the assignor, the UK IPO will usually consider the form to be sufficient evidence to proceed to register the assignment and will not usually require any additional evidence. If the form is not signed by the assignor, documentary evidence of the assignment (for example, a copy of the assignment document) must be filed with the form. There is a GBP50 fee for filing the form.

There is no formal requirement for a licence to be in writing in order to be valid, but it is recommended that licences are granted in writing to ensure clarity as to the terms of the licence.

As with assignments, there is no requirement to register a licence at the UK IPO. However, it is recommended to do so, as failing to register a licence can have significant consequences.

  • Third parties can acquire interests in a patent or patent application without being bound by an earlier unregistered licence (unless they otherwise knew of the licence).
  • In addition, an exclusive licensee who does not register a licence within six months of the effective date of the licence is not able to claim costs or expenses in proceedings for infringement of that patent where that infringement took place prior to registration.
  • A failure to register an exclusive licence can give rise to difficulties establishing that the exclusive licensee is entitled to bring proceedings against a third party in their own right.

The process for registering a licence of a UK patent or patent application is the same as the process for registering an assignment of a UK patent or patent application, as described in 10.2 Procedure for Assigning an Intellectual Property Right.

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Kirkland & Ellis International LLP has a patent litigation practice comprised of approximately 230 attorneys in London, Austin, Boston, Chicago, Houston, Los Angeles, New York, Palo Alto, Salt Lake City, San Francisco and Washington, DC. More than 75% of Kirkland’s patent litigation attorneys are engineers and scientists, trained in a variety of technical disciplines. Kirkland’s experienced IP litigation attorneys achieve extraordinary results in patent, copyright, trade mark, trade secret misappropriation and advertising matters. They represent clients across a broad range of industries, including life sciences, technology, consumer products manufacturing, financial services, automotive, and food and beverage. Other areas of practice are pharmaceutical and biologics patent litigation, co-ordinating global IP enforcement/defence cases, SEPs and FRAND disputes, post-grant proceedings before the US Patent and Trademark Office’s Patent Trial and Appeal Board, and appeals of high-stakes cases in the US Court of Appeals for the Federal Circuit and the US Supreme Court, as well as the Court of Appeal of England and Wales and the UK Supreme Court.