The Motion Picture Association is attempting to force the UK's biggest internet service provider to block access to a pirate website.
It's filed for an injunction against BT, demanding that it cut off access to Newzbin for its 5.6 million customers.
Newzbin makes over £1 million a year, says the MPA, by offering its subscribers links to movie, television, music and software downloads.
The MPA, the international arm of the Motion Picture Association of America, won a High Court order against Newsbin last year - but to no real effect, as Newzbin promptly went into administration.
After it reappeared within weeks, under new management and based in the Seychelles, the MPA decided to go after BT instead. Similar blocking orders have successfully been won in other countries, particularly Italy. But it's the first time it's been attempted in the UK.
There's a reason the MPA went after BT in particular. Back in 2004, the company introduced a system called Cleanfeed, designed to prevent access to child pornography. It means BT already has a mechanism in place to block sites on the IP address level.
BT also supplies the Cleanfeed system to other ISPs, meaning that a victory against BT could potentially lead to action against them too.