The basics of patent law - revocation, non-infringement and clearing the way

30 March 2017

Gowling WLG's intellectual property (IP) experts discuss challenges to validity, revocation actions, non-infringement and other procedures to remove the effect of an IP right, as part of their 'The basics of patent law' series.

The articles cover, respectively: Types of intellectual property protection for inventions and granting procedure; Initiating proceedings; Infringement and related actions; Revocation, non-infringement and clearing the way; Trial, appeal and settlement; Remedies and costs; Assignment and Licensing and the Unified Patent Court and Unitary Patent system.

The articles underpin Gowling WLG's contribution to Chambers' Global Practice Guide on Patent Litigation 2017, for which Gordon Harris and Ailsa Carter wrote the UK chapter.


Pursuant to the Patents Act 1977 (also referred to below as "PA"), section 72, a claim for revocation of a patent may be brought in the court or before the Comptroller-General of Patents, Designs and Trade Marks (the "Comptroller"; i.e. the UK Intellectual Property Office).

In England and Wales, the appropriate 'court' is the Patents Court or the Intellectual Property Enterprise Court, both of which form part of the Chancery Division of the High Court. In Scotland, the appropriate court for claims under the Patents Act is the Court of Session. Choice of court is discussed in more depth in our article titled 'Initiating proceedings'.

Where an application to the Comptroller has been made but has not yet been disposed of, the applicant may not apply to the court under the same section of the Patents Act (i.e. for revocation) in respect of the same patent without the agreement of the proprietor or the Comptroller's written certification that the question of whether the patent should be revoked would more properly be determined by the court.

Where the applicant is unsuccessful before the Comptroller, no application (other than by way of appeal or by way of putting validity in issue in proceedings for infringement) may be made to the court by that person under the same section of the Patents Act (i.e. for revocation), without the leave of the court (PA s.72(6)).

Proceedings in which the validity of a patent may be put in issue

The Patents Act, section 74, provides an exhaustive list of the circumstances in which the validity of a patent may be put in issue:

  • by way of defence, in proceedings for infringement of the patent (pursuant to s.61 or s.69 (for infringement of rights conferred by publication of an application));
  • in proceedings for groundless threats of patent infringement proceedings (pursuant to s.70);
  • in proceedings in which a (statutory) declaration of non-infringement is sought (pursuant to s.71);
  • in proceedings for revocation pursuant to s.72 (discussed below);
  • in disputes relating to the "Crown use" provisions of the Patents Act (discussed in our article titled 'Infringement and related actions').

The validity of a patent may not be put in issue in any other proceedings. In particular, no proceedings may be instituted seeking only a declaration regarding the validity or invalidity of a patent.

Grounds for revocation

Revocation may be sought on one or more of the following grounds (PA s.72);

  1. the invention is not a patentable invention;
  2. 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;
  3. the matter disclosed in the specification of the patent extends beyond that disclosed in the relevant application as filed;
  4. the protection conferred by the patent has been extended by an amendment that should not have been allowed;
  5. the patent was granted to a person who was not entitled to be granted that patent.

Not a patentable invention

Point i) refers to the conditions for patentability (PA s.1-4 & Sch. A2), the challenges under this head being that the patent lacks novelty, does not involve an inventive step, is not capable of industrial application or is otherwise excluded.

A concept central to patentability is the 'priority date' of the patent. The priority date of a patent is the date on which the application was filed, unless priority is claimed from an earlier patent application. Such an earlier application is described as a "priority document" and must have been made within up to one year before the later application, anywhere in the world, by the applicant or his predecessor in title. For a patent or application to be entitled to the claimed priority, the priority document must also describe the same invention. If the later application is entitled to the claimed priority, its 'priority date' will be the date on which the earlier patent application was filed.


A patent will lack novelty (or be "anticipated") if it forms part of the "state of the art". The state of the art comprises all matter which has at any time before the priority date been made available to the public (whether in the UK or elsewhere) by written or oral description, by use or in any other way. The content of earlier filed (but not yet published) UK patent applications and European patent applications designating the UK is included as part of state of the art for the assessment of novelty. Specific matters forming part of the state of the art are often referred to as "prior art" or, sometimes, "prior use".

In order to anticipate, there must be a disclosure of something within the scope of the claim, and the 'skilled addressee' must be able to perform the claimed invention using the matter disclosed in the prior art, read and understood together with his common general knowledge (Synthon v SKB [2005] UKHL 59).

The 'skilled addressee' or 'person skilled in the art' is the hypothetical person (which may be a team) to whom the patent is addressed and who is likely to have a practical interest in putting into effect the technical subject matter of the patent.

The 'common general knowledge' may be described as that which is generally known and regarded as a good basis for further action by those who are engaged in the particular art, or as the technical background of the person skilled in the art (Smith & Nephew v KCI Licensing [2010] EWCA Civ 1260). The common general knowledge may include material which the skilled addressee knows to be available online and which is generally accepted as a good basis for further action (such as material which might be found off-line in a textbook or a key journal article) (GlaxoSmithKline v Wyeth [2016] EWHC 1045 (Ch)).

The assessment of anticipation is conducted as at the date of each relevant prior art or prior use. In practice the claimed subject-matter must be compared individually and in turn with each piece of prior art, or prior use, relied upon.

Inventive step

A patent will lack inventive step (or be "obvious") if the claimed invention was "obvious to a person skilled in the art, having regard to any matter which forms part of the state of the art". Earlier filed but not yet published patent applications are not included in the state of the art for the assessment of inventive step.

On the law regarding inventive step/obviousness, an often-quoted statement of principle is that made by Kitchin J at first instance in Generics v Lundbeck [2007] EWHC 1040 (Pat), approved by Lord Hoffmann in the House of Lords in Conor v Angiotech [2008] UKHL 49:

"The question of obviousness must be considered on the facts of each case. The court must consider the weight to be attached to any particular factor in the light of all the relevant circumstances. These may include such matters as the motive to find a solution to the problem the patent addresses, the number and extent of the possible avenues of research, the effort involved in pursuing them and the expectation of success."

There is only one statutory question, namely, whether the invention was obvious at the priority date. This is a multifactorial assessment, to be considered on the facts of each case, and the court must consider the weight to be attached to particular facts in the light of all the relevant circumstances. These include the motive to find a solution to the problem that the patent addresses, the number and extent of possible avenues of research and the effort involved in pursuing them. (See Hospira v Genentech [2016] EWCA Civ 780; Generics v Lundbeck [2007] EWHC 1040, Conor v Angiotech [2008] UKHL 49).

Whether the invention was "obvious to try" is not a substitute for the statutory test, but may be one of many considerations which it may be appropriate for the court to take into account in assessing the statutory question, and must in any case be coupled with a reasonable or fair prospect of success. A judge's assessment of whether an approach has a reasonable or fair prospect of success is itself another multifactorial assessment. The skilled person may be faced with a range of obvious possibilities, making it statistically unlikely that he will settle on any of them, but they will all be obvious. (Hospira v Genentech [2016] EWCA Civ 780, Brugger v Medicaid (No.2) 1996 RPC 635).

In practice, the court will consider each piece of prior art or prior use relied upon, and the claimed invention as construed, and consider whether the claimed invention was, at the priority date, obvious to the person skilled in the art in light of their common general knowledge. Multiple disclosures (for example, different publications relied upon by the party challenging validity) can only be combined if it would have been uninventive for the skilled person to do so and in practice such situations are rare.

Industrial application

A patent will lack industrial application if it cannot be "made or used in any kind of industry, including agriculture". The notion of industry is construed broadly (Eli Lilly v Human Genome Sciences [2008] EWHC 1903 (Pat)).

Other exclusions

The exclusions from patentability referred to are:

  1. anything which consists of (s1(2)):
    - a discovery, scientific theory or mathematical method;
    - a literary, dramatic, musical or artistic work or any other aesthetic creation;
    - a scheme, rule or method for performing a mental act, playing a game or doing business, or a program for a computer; or
    - the presentation of information;
    (although this category of exclusion only prevents the patentability of the thing as such);
  2. inventions of which the commercial exploitation would be contrary to public policy or morality (s1(3)-(4));
  3. methods of treatment of the human or animal body by surgery or therapy (s4A);
  4. methods of diagnosis practised on the human or animal body (s4A);
  5. the human body, at the various stages of its formation and development, and the simple discovery of one of its elements, including the sequence or partial sequence of a gene (Schedule A2, s3(a));
  6. processes for cloning human beings (Schedule A2, s3(b));
  7. processes for modifying the germ line genetic identity of human beings (Schedule A2, s3(c));
  8. uses of human embryos for industrial or commercial purposes (Schedule A2, s3(d));
  9. processes for modifying the genetic identity of animals which are likely to cause them suffering without any substantial medical benefit to man or animal, and also animals resulting from such processes (Schedule A2, s3(e));
  10. any variety of animal or plant or any essentially biological processes for the production of animals or plants, not being a micro-biological or other technical process or the product of such a process (Schedule A2, s3(f)).


Point ii) is generally described as an "insufficiency" challenge. The statutory requirement for such a challenge to succeed is that "the specification of the patent does not disclose the invention clearly enough and completely enough for it to be performed by the person skilled in the art". In the jurisprudence, different kinds of insufficiency have been identified, namely that:

  • the skilled person cannot perform the claimed invention at all (i.e. to produce something falling within a claim) or without undue burden;
  • the claimed invention lacks 'plausibility';
  • the claim is excessively broad having regard to the patentee's technical contribution to the art; or
  • the claim is ambiguous (such that the skilled person could never know if they were within it or not).

(See Idenix v Gilead [2016] EWCA Civ 1089, Warner-Lambert v Generics [2016] EWCA Civ 1006, Generics v Yeda [2012] EWHC 1848 (Pat)), Kirin-Amgen v Hoechst Marion Roussel [2005] UKHL 46).

A challenge of insufficiency is considered by reference to the person skilled in the art and in light of the information in the specification and the common general knowledge, at the filing date of the patent.

Added matter

Point iii) is generally described as an "added matter" challenge. The courts consider whether a skilled person would, upon looking at the amended specification, learn anything about the invention which he could not learn from the application as filed/the unamended specification (Teva v Leo [2015] EWCA Civ 779, Vector v Glatt [2007] EWCA Civ 805, Nokia v IPCom [2013] EWCA Civ 567, Rickardson-Vick's Patent [1995] RPC 568). The same general considerations arise under section 76(2) of the Patents Act, which prohibits amendment to a patent application that would extend the matter disclosed beyond that disclosed in the application as filed.

Extension of scope

Point iv) is generally described as an "extension of scope" challenge. It rarely arises in the case law as it only concerns amendments made to claim language after the grant of a patent which result in the claims covering more than at grant. The same considerations apply under section 76(3)(b) of the Patents Act, which prohibits amendments to the patent that would extend the protection conferred by the patent.

Grant to a person not entitled

Point v) of the grounds for revocation listed at the start of this section permits a party who has been found by the court or the Comptroller to be entitled to the patent or a part of the matter comprised in it, to seek revocation of the patent on the ground that it was granted to a person who was not the person (or was not the only person) entitled to be granted that patent.

The above grounds represent a complete codification of the grounds for revoking a patent.


In any proceedings before the court or the Comptroller in which the validity of a patent is or may be put in issue the court/Comptroller may allow the proprietor of the patent to amend the specification of the patent, subject to such terms as to advertising and costs as the court or Comptroller thinks fit. Whether the court permits the requested amendment depends upon whether the proposed amendments would result in a valid patent, and also upon the timing and form of the application.

In such proceedings, an application to amend should be made by notice in accordance with Civil Procedure Rule 63.10, giving particulars of the proposed amendment sought, the grounds upon which it is sought, and stating whether the applicant will contend that the existing claims are valid. It is possible for the proprietor to make a 'conditional' application to amend the patent and/or its claims, in the event the patent (or some claims of it) is considered invalid. The application notice must be served on the other parties to the litigation and the Comptroller.

An application for amendment made with appropriate notice before trial of the validity dispute will usually be considered by the Court (see, for example, Meter-Tech v British Gas [2016] EWHC 2278 (Pat)). On the other hand, an application made after claims have been held invalid will usually not be permitted (see, for example, Generics v Warner-Lambert [2016] EWCA 1006 (Pat)).

Where the court or Comptroller determines that only some claims of the patent are invalid, it may order that the patent should be revoked unless within a specified time the specification is amended to the satisfaction of the court/Comptroller (PA s.72(4)). In accordance with this, an application made after a finding of invalidity, to amend the patent by deleting the claims found to be invalid, will usually be uncontroversial.

Declarations of non-infringement

Pursuant to the Patents Act, section 71, a party may apply to the court or the Comptroller for a declaration that an act does not, or a proposed act would not, constitute an infringement of a patent. It must be shown that, prior to seeking the declaration, that person has applied in writing to the proprietor for a written acknowledgment to the effect of the declaration or declaratory claimed, and has furnished him with full particulars in writing of the act in question, and that the proprietor has refused or failed to give any such acknowledgement.

Any issue as to whether an act, or proposed act, does or would infringe a patent is assessed as described in our article on Infringement and related actions.

Validity issues may be put in issue in s.71 proceedings, but a claim for revocation should also be made if revocation is sought in addition to the declaration of non-infringement. When proceedings relating to the patent are pending in the court, a s.71 action cannot be brought before the Comptroller without the permission of the court (PA s.74(7)).

A declaration of non-infringement made by the Comptroller pursuant to s.71 has the same effect as a declaration by the court, but it does not prevent any party to court proceedings for infringement from alleging invalidity of the patent, irrespective of whether any such issues were considered in the context of the declarative proceedings before the Comptroller.

In addition to the statutory power, the court has an inherent power to grant declarations of non-infringement where such a declaration would serve a useful purpose. In some respects, this power is wider than the statutory power. It includes, for example, power to make declarations in respect of non-UK designations of European patents (Actavis v Lilly [2013] EWCA Civ 517).

Other declaratory relief

In Fujifilm Kyowa Kirin Biologics ("FKB") v AbbVie [2017] EWHC 395 (Pat), the Patents Court awarded, in a landmark judgment, a novel type of declaratory relief that the administration of FKB's proposed products in the treatment of a particular medical indication by a particular dosing regimen would have been obvious at a particular date. The facts of the case were unusual, but the court concluded that granting such a declaration would serve a useful purpose in view of AbbVie's patent filing strategy, in particular AbbVie's strategy of abandoning its patents in favour of filing divisional patent applications which were incapable of challenge in the UK courts, and in light of public statements made about the strength of and intentions to enforce its patent portfolio.

Jurisdiction of the Comptroller to issue an opinion

Additionally, the Patents Act, s.74A, provides that the proprietor of a patent or any other person may request the Comptroller to issue an opinion on a prescribed matter in relation to the patent. The prescribed matters are defined in the Patents Rules 2007, section 93, and include questions of patentability, sufficiency, added matter and extension of scope. The prescribed matters also include questions of infringement (or non-infringement). Such opinions are not binding for any purposes.

Comptroller's power to revoke patents on his own initiative

Where the Comptroller issues an opinion under s.74A that the patent lacks novelty or lacks inventive step, the Comptroller may revoke the patent, but not before the patentee has had the opportunity to seek (and obtain) a review of the opinion. The patent proprietor must also be given an opportunity to make observations and amend the specification of the patent (PA s.73(2)).

Further, if it appears to the Comptroller that a patent lacks novelty in view of the content of an earlier filed (but not yet published) UK or European patent application, the Comptroller may on his own initiative by order revoke the patent. However, the proprietor of the patent must first be given an opportunity of making any observations and of amending the specification so as to exclude any matter which formed part of the state of the art. (PA s.73)

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