Moorcrofts Corporate Law, argued last week.that Linux and other open-source software . Although the company has refused to say which patents are involved, because the company has far fewer patents in the U.K., Andrew Katz, a solicitor at
However, on the IPKat blog.affecting the U.K. than the 51 U.K. patent applications Katz quoted, because Redmond also has a few hundred European patents , depending on the decisions of U.K. courts, said David Pearce, an associate at Nottingham-based patent attorneys Eric Potter Clarkson,
Katz points out, though, that "even if 400 (patents) apply in the U.K., this is a vastly smaller number than the amount that apply in the U.S. It demonstrates that the U.K. regime is vastly different to the U.S. regime, which is the main point that needs to be drawn out."
According to Katz, the European Patent Office has granted 431 patents to Microsoft, out of 4,341 applications. More than 7,000 patents have been granted to Microsoft in the U.S.
European patents are more attractive than U.K. patents, explained Pearce. "For obvious reasons, and not just those relating to cost, most big companies nowadays much prefer to prosecute their patent applications before the European Patent Office rather than the U.K. Intellectual Property Office."
Of Microsoft's 431 European patents, many will be irrelevant to the Linux case because they deal with hardware issues such as mice.
"In a very brief and nonscientific scan of the 51 applications made through the U.K. patent office, the proportion of patents which were hardware-related seemed significantly higher than a quick, random sample of (Microsoft's) U.S. patents," said Katz.
Europe's stance against software patents is not as firm as Katz said, according to Pearce. "Europe does indeed 'do' software patents, and has done for many years," he said.
Since 1999, patents have been issued for computer program products according to complex criteria. "(It) depends on something to do with a 'technical effect'--that is, an effect beyond that of a mere computer program," Pearce explained. "This is easier to understand when computers are used to control industrial processes, but less so when applied to general-purpose computer applications."
These criteria are just "loopholes" by which patent agents try to get around a European statutory exclusion for the patentability of computer software, Pearce said. The European Patent Convention and the United Kingdom Patents Act "make it clear that computer software 'as such' is not patentable. This obviously generates a lot of debate as to what 'as such' means."
If its Linux patents are legal in the U.K.,for "indirect infringement"--a supplier of computer programs providing the means to put Microsoft's invention into effect--rather than "direct infringement"--a supplier providing infringing computer programs.
"The difference is one of level and burden of proof, and effectively makes it harder to enforce the relevant patents," said Pearce. "The patents would not, however, necessarily be invalid as a whole, just in part. This would not prevent Microsoft from suing anyone--just make it a bit harder for them to win."
So both Katz and Pearce agree that Microsoft is much less likely to bring any patent infringement cases against open-source users in the U.K. The U.K. Intellectual Property Office doesn't grant computer program patents anymore--ever since two recent applications (submitted by Aerotel Medical Systems) were rejected.
However, the status of patents already in existence is not clear without more case law, said Pearce.
Peter Judge of ZDNet UK reported from London.