The patentability of software is a controversial area of UK intellectual property law. The question seemed to be settled in a decision by the Court of Appeal in 2006 which outlined how courts should determine whether an invention consists purely of software, and therefore should not be awarded a patent.
That ruling took in two cases, one involving a company called Aerotel and another involving inventor Neal Macrossan.
In a judgment handed down today, the High Court apparently says that the UK-IPO was wrong to reject a patent application for an invention by London-based company Symbian.
The UK-IPO said in a statement that the judge did not apply the methodology outlined by the Court of Appeal in the Aerotel/Macrossan case. It will appeal the case because it believes that the new ruling makes it unclear what approach should be taken to software patent applications.
"The UK-IPO believes that when deciding whether this computer implemented invention is patentable, Mr Justice Patten did not apply the so-called 'Aerotel/Macrossan test', which was established by the Court of Appeal in the way intended," said a UK-IPO statement. "This in UK-IPO's view has created uncertainty about how the Aerotel/Macrossan test should be applied for inventions of this type."
Symbian makes operating systems for mobile devices and its invention in this case was related to the indexing of library functions to ensure operating system stability. It was awarded a patent by the European Patent Office (EPO) which has different rules on software patents.
The UK-IPO said that Mr Justice Patten's ruling in the High Court pointed out the discrepancy between EPO rules and UK-IPO ones.
The UK-IPO said that it will continue to decide on inventions' patentability based on the guidance it published previously, which itself is based on the Aerotel/Macrossan ruling. It did say, though, that it would "take account of the Symbian judgment in appropriate cases".
The UK-IPO has faced criticism before from courts on how it applied the Aerotel/Macrossan rulings to its own guidelines. In a High Court case in January Mr Justice Kitchin said that the UK-IPO had rejected some patent applications on the software grounds that they should have accepted.
"The question I must now consider is whether the decision prohibits the patenting of all computer programs and, in particular, those which under the old approach would have been considered to make a conventional computer operate in a new way so as to deliver a relevant technical contribution," wrote Mr Justice Kitchin in his High Court ruling.
"UK-IPO has apparently concluded that it does and so has reverted to its previous practice of rejecting all computer program claims … I do not detect anything in the reasoning of the Court of Appeal which suggests that all computer programs are necessarily excluded," he wrote.
The original UK-IPO application by Symbian was heard by Mrs S E Chalmers. She applied the four-step test laid out in the Aerotel/Macrossan ruling and found that the invention was a computer program and nothing more, and therefore could not be patented.
"The actual role of the DLL [dynamic link library] has not been changed by the claimed invention - it still provides exactly the same functionality as it had before," she wrote in her ruling. "What has changed is the manner in which the DLL has been accessed – it is now done by an additional piece of software in the form of the interface. I therefore find that the contribution made by the claims on file, the main claims and the first auxiliary claims boils down to nothing more than a computer program and hence is excluded from patentability."