BT has launched a lawsuit against Google, claiming the Android operating system infringes some of its patents.
The lawsuit, which has been filed in the US, relates to six patents that BT says Google Maps, Google Music and the Android Market infringe. All but one of the patents concerned were awarded to BT in the 1990s. If successful, Google will be required to pay damages, which could hit billions of dollars, as well as seeing an injunction imposed.
BT has not revealed whether it will also file the lawsuit in the UK or the rest of Europe.
"BT brings this action to recover the just compensation it is owed and to prevent Google from continuing to benefit from BT's inventions without authorisation," BT says in the filing, which has been published by intellectual property analyst, Florian Mueller.
Mueller said BT probably wants to continue to be able to do business with all mobile device makers and therefore decided to sue Google itself.
"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," he added.
BT's lawsuit isn't the only one Google is facing over patent infringement by its Android operating system, Apple. Oracle, Microsoft, eBay and digital security company Gemalto all have launched legal action regarding Android.
Google told Cnet it believes the claims "are without merit, and we will defend vigorously against them".