Back in 2011 we first heard of BT's attempt to sue Google over its use a broad series of tech patents supposedly under BT's ownership. Now Google's striking back in what looks like little more than a revenge attack to gain some bargaining chips.

Google's latest claim covers four patents that BT uses in its business offerings, covering such mundane features as conference calling over IP networks and quality assurance technologies.

Google isn't making itself look like the good guy here, with a statement on the case making it sound like it's going after BT for the sake of it. A Google spokesperson said of the latest case: "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 kind of actions, we will defend ourselves."

BT's original case against Google, which covers unrelated patents used in the Android OS, is still ongoing. [Reuters via TechCrunch]