Eleven years ago, BT attempted to enforce patent number 4,873,662. It approached a number of big US ISPs and basically said "we own hyperlinks. Pay up or else". The courts eventually told BT to get bent, but if the firm had won it would have had a chilling effect on the web.

That was a long time ago, of course, and things are different now - but BT is once again throwing its patent weight around the place. This time, though, the target is Android.

BT reckons that Android (and Google Maps, and Google Music, and Gmail) infringe six of its patents, so it's suing Google for what it's safe to assume is a huge pile of money.

Google isn't the only target. Manufacturers can barely say "Look! A new Android thing!" before somebody clobbers them with a lawsuit. Thanks to Apple, HTC has been told that if it doesn't remove a "small UI experience" from its Android handsets by April, it won't be able to sell them in the US, and Samsung's court battles with Apple have been going on for months.

Apple's going after HTC and Samsung, BT's going after Google and Microsoft is cleaning up: with Android-related royalties coming in from the likes of HTC, Samsung, General Dynamics, Acer, Viewsonic and many more, some claim that Microsoft now makes more money from Android firms' licences than it does from its own Windows Phone. If BT's legal action is successful, it'll be getting some royalty action too.

For a free operating system, Android's looking awfully expensive.