BT has been given 14 days to block access to Newzbin2, a website accused by Hollywood studios of promoting illegal file-sharing "on a grand scale", in a ruling by the UK's High Court.
In the first judgement of its kind under UK copyright law, Justice Arnold ruled in favour of a consortium of film industry giants, including Warner Bros, Paramount, Disney, Universal, Fox and Columbia, enforcing an earlier judgment that the site had made millions by exploiting others' work.
BT - Britain's largest ISP, with a customer base of around six million - must comply with the court order by blocking access to all of its subscribers within the two weeks.
Justice Arnold also pre-emptively moved to prevent access to the site via other means. He ordered BT to block "any other IP address or URL whose sole or predominant purpose is to enable or facilitate access to the Newzbin website", preventing the site from reaching BT customers from another location on the web.
"I do not consider that the studios should be obliged to return to court for an order in respect of every single IP address or URL that the operators of Newzbin2 may use," he explained.
The court also ordered BT to pay for the cost of implementing the block on Newzbin2.
BT, which argued that the film studios should pay, estimates the cost of the block to be around £5,000, and £100 for each subsequent notification.
The judge said BT customers would not be able to sue the ISP for breach of contract in respect of the block, because such a move is covered by the acceptable use policy of its broadband package, which bans users from activities that infringe copyright.