In an atypical move, Google has filed a patent infringement suit against BT's American operation and its VoIP services, charging them with treading on Google IP related to network communications.

FOSS Patents says the filing means that Google CEO Larry Page will never again be able to say, "We've never sued anyone over patents."

Google wants damages and an injunction preventing any further infringement of its four patents.

It's tit for tat. BT accused Google of infringing six of its mobile device patents in a 2011 suit that indicts Android, Gmail and Google Maps.

Google claims, "We have always seen litigation as a last resort, and we work hard to avoid lawsuits. But BT has brought several meritless patent claims against Google and our customers - and they've also been arming patent trolls. When faced with these kinds of actions, we will defend ourselves."

Google filed its complaint in federal court in Los Angeles as well as in a UK court.

The original BT complaint is still pending in Delaware.

A non-practicing entity called Suffolk Technologies LLC sued Google in Virginia using a patent that had belonged to BT. Google got three of the patents it's using against BT from IBM. The remaining patent used to belong to Fujitsu. Google also armed HTC with patents to sue Apple.