To be patentable, software must provide a ‘technical contribution' to the state of the art as at the priority date of a patent application. The case of Lantana Ltd v Comptroller, recently decided by the Court of Appeal, provides valuable insight into the way patent applications for computer software should be dealt with in the UK. In particular, the Court has clarified how the ‘contribution' aspect of the ‘technical contribution' should be determined.

The Patents Act 1977 excludes certain categories of inventions from being patentable. Programs for computers, business methods, mathematical methods and presentations of information etc. are all subject matter excluded from patentability ‘as such'. This ‘as such' exclusion still allows for many patents to be granted for, for example, computer software, where the subject matter provides a so-called ‘technical contribution'.

The law has been somewhat uncertain since the Court of Appeal introduced the current tests for excluded subject matter in Aerotel. Subsequently, the High Court, in Gemstar v Virgin, refused to decide whether the ‘contribution' should be considered with respect to the state of the art or mere common general knowledge. In a later High Court decision (HTC v Apple) Floyd J considered that it should be with respect to the state of the art, although his remarks were strictly obiter.

The Court of Appeal has now made it clear that the correct approach should be to consider "the actual contribution to the art which the invention has made" (per Kitchin LJ at para. 65). The consequence of this is that whether a ‘technical contribution' exists or not will depend on what was known in the state of the art at the priority date of the patent application.

The judgement in Lantana also emphasizes that substance takes precedence over form. Therefore, where an inventor has a patentable idea that contributes something new and inventive over the state of the art at the priority date, it should make no difference whether the idea is claimed in the form of software or hardware; patent protection should be available in either case.