The UK's biggest service provider, BT, has become the latest company to sue Google claiming patent infringement.
It says the company's infringing on six patents covering elements of service provision based on network type, a navigation system, location services and digital rights management. All were granted between 2000 and 2004.
Infringing services, claims the lawsuit, include 'Google's storage, retrieval and delivery of location-based information through its search engines, Android, AdMob, AdSense, AdWords, AdWords Express, DoubleClick, Gmail, Google+, Google Docs, Google Maps, Google Offer and Google Places'.
BT's one of the biggest telecoms companies in the world, with operations on over 170 countries worldwide. It's filed its suit in the US, in the District Court of Delaware, but could easily launch another in Europe.
In claiming Android infringes its patents, BT joins Apple, Oracle, Microsoft eBay and Gemalto, amongst others, leaving the platform more vulnerable than ever. Unlike some of these, though, it isn't suing handset makers too, presumably because it wants to keep a good relationship with them.
"With so many major patent holders asserting their rights, obligations to pay royalties may force Google to change its Android licensing model and pass royalties on to device makers," says patent expert Florian Mueller.
"Android already had more than enough intellectual problems anyway. Now Google faces one more large organization that believes its rights are infringed."