It's supposed to be pretty clear that computer software cannot be patented in Europe: the Patents Act in the UK, and the European Patent Convention, both say unequivocally that a program for a computer as such cannot be the subject of a patent. But those two little words open up a huge range of possibilities for securing a patent for an invention that isn't really much more than a computer program.

Last year, the Court of Appeal elaborated on the subject – one that it has looked at several times already – in Aerotel v Telco and Macrossan's Application. It set out a new four-stage test for determining whether a computer-related invention would be excluded from patentability, based on an examination of what the patent documents claim:

  • Construe the claim; 
  • Identify the contribution of the invention as claimed to the state of the art; 
  • Ask whether that contribution consists solely of excluded matter (a computer program, for example); 
  • Check whether that contribution is technical.

On 13 March, the Patents Court applied these new rulings in two cases, appeals against refusals of patents brought by one Pablo Cappellini and by Bloomberg LP.

Mr Cappellini had devised a new algorithm that helped set the route to be taken by a carrier delivering packages. Bloomberg's invention was a method of distributing in which the data transmitted to a user were ‘mapped’ to a more usable format. Both appeals were rejected on the grounds that the inventions lacked a technical effect; they related only to schemes, rules or methods for performing mental acts. Bloomberg's innovation was an improvement to a computer program, while Mr Cappellini's produced no physical or real world effect.

The case does, however, make clear that there is scope for an inventor to ‘tether’ the invention to a real-world effect or a real article. Whether an invention is patentable or not will often turn on how the invention is presented in the patent application, for it may be nothing more than a matter of how it is described. The loophole has always been there, but these recent cases have given the courts the opportunity to describe how to fit through it.