There are four overriding requirements for a patent to be granted under United Kingdom patent law. Firstly, there must have been an invention. That invention must be novel, inventive and susceptible of industrial application. (See Patentability.)
Patent laws in the UK and throughout Europe specify a non-exhaustive list of excluded things that are not regarded as inventions to the extent that a patent application relates to the excluded thing as such. This list includes programs for computers.
Despite this, the United Kingdom Intellectual Property Office (UKIPO) regularly grants patents to inventions that are partly or wholly implemented in software. The extent to which this should be done under the current law and the approach to be used in assessing whether a patent application describes an invention has been settled by the Court of Appeal. The UK approach is quite different from that of the European Patent Office (EPO), although "there should be no significant difference in result."
Globally, the extent to which patent law should allow the granting of patents involving software (often referred to as "software patents") is controversial and also hotly debated (see Software patent debate).
Substantive law
Although it is an implicit requirement of Section 1(1) of the UK Patent Act (1977) that patents should only be granted for inventions, "invention" is not defined anywhere in the Act.
Instead, Section 1(2) Patents Act provides a non-exhaustive list of "things" that are not treated as inventions. Included in this list is "a program for a computer". However, these things are only prevented from being treated as inventions "to the extent that a patent or application for a patent relates to that thing as such".
Article 52(2) of the European Patent Convention (EPC) includes a slightly different list of non-inventions, although "programs for computers" are present. Article 52(3) EPC then states that patentability for the identified subject matter or activities is excluded "only to the extent to which a European patent application or European patent relates to such subject-matter or activities as such".
The wording of the Patents Act is slightly different from Article 52 EPC, but the UK Courts have taken the view that since the purpose of Section 1 of the Patents Act was to transpose the requirements of Article 52 EPC into UK law, any differences between the EPC and the Patents Act should be ignored. The text of the EPC itself should therefore be regarded as definitive.
Other things that are not regarded as inventions include mathematical methods, and schemes, rules and methods for performing mental acts, playing games or doing business. These additional excluded categories often overlap with the exclusion of computer programs since they may be put into practice using a computer.
Case law
Summary
The case law in the United Kingdom relating to excluded subject matter in general, and computer programs specifically, has a somewhat sporadic history. For eight years, the leading case in the UK over whether or not a patent or patent application involving the use of a computer program related to an invention, or whether it instead related to a computer program "as such" was the judgment in Fujitsu's application from 1997.
Only in 2005, in the judgment in CFPH LLC's applications, did the UK Courts again consider the issue of excluded subject matter in detail. In the meantime, the practice of the EPO and the UKIPO had diverged significantly. In some ways this judgment brought UK law closer to the practice of the EPO; but it also criticised the reliance of the EPO on paraphrasing the exclusions from patentability under the blanket heading of "technical".
Subsequently, in October 2006, the Court of Appeal heard their first case relating to the validity of computer programs in nine years and handed down their judgment on the matter of Aerotel v Telco and Macrossan's Application. This judgment reaffirmed the reasoning in Fujitsu and once again moved the practice of the UKIPO away from that of the EPO.
Court of Appeal judgments
Fujitsu's Application
Fujitsu's Application was considered by the Court of Appeal in 1997. The case in question had been refused by the UKIPO and by J Laddie on Appeal before the High Court. LJ Aldous heard the appeal before the Court of Appeal and his judgment is notable for several reasons: