9.4 Patent invalidity
Section 72(1) of the Act provides that any person62 may bring a claim before the court (again, that is to say, the High Court in England and Wales)63 or the Comptroller for revocation of a patent64 on the following grounds:
- (a) the invention is not a patentable invention;
- [… ]
- (c) the specification of the patent does not disclose the invention clearly enough and completely enough for it to be performed by a person skilled in the art;
- (d) the matter disclosed in the specification of the patent extends beyond that disclosed in the application for the patent, as filed […];
- (e) the protection conferred by the patent has been extended by an amendment which should not have been allowed.65
Grounds (a), (c) and (d) correspond to those available in EPO opposition proceedings under Article 100(a)–(c) of the EPC.
The same grounds of invalidity may also be raised in response to a claim for infringement (either only by way of a defense or also in a counterclaim for revocation), in a claim for a declaration of non-infringement under Section 71 of the Act (see Section 9.5.4 below) and in threats proceedings (see Section 9.5.5 below).66 However, threats proceedings can only be brought before the court, and claims for infringement may only be brought before the Comptroller with the consent of the parties.
In response to a claim for revocation (whether before the court or the Comptroller), a patent proprietor may apply for permission to amend the patent under Section 75 of the Act. The amendment will not be allowed if it results in the patent disclosing additional matter or extends the protection conferred by the patent67 or if it introduces a lack of clarity to the claims.68 The procedure for applying for permission to amend a patent is addressed in Section 9.6.6 below.
If the grounds of invalidity are established, the order for revocation may be unconditional or, where the court or the Comptroller determines that the patent is invalid only in part, an order that the patent should be revoked unless amended to its satisfaction.69
Conversely, if the patent is held to be wholly or partially valid, the court or the Comptroller may grant a certificate of contested validity. The effect of such a certificate is that, in any subsequent proceedings for infringement or revocation of the patent in which a final order is made in favor of the party relying on the validity of the patent, that party is entitled to their costs at first instance (but not on any appeal) on an indemnity basis.70