Patent Claims

A patent does not protect everything described in its specification — it protects only what is claimed. Section 125 of the Patents Act 1977 makes this the governing rule: an invention protected by a patent or patent application 'shall... be taken to be that specified in a claim of the specification of the application or patent, as the case may be, as interpreted by the description and any drawings contained in that specification, and the extent of the protection conferred by a patent or application for a patent shall be determined accordingly.'

Claims are therefore the operative legal text of a patent — everything else in the specification (the detailed description, drawings, background) exists mainly to explain and support the claims, and to aid their interpretation, rather than to independently define the scope of protection. Section 125(1) also incorporates the Protocol on the Interpretation of Article 69 of the European Patent Convention, which steers courts away from both an overly literal reading of the claim wording and an overly loose approach based only on the general inventive concept, aiming instead for a fair middle position that gives the patentee reasonable protection with reasonable certainty for third parties.