UK arts lobby groups have demanded BT block access to the BitTorrent file sharing website, The Pirate Bay.
Music industry trade body, the BPI, said it would take legal action if the telecoms firm refused to co-operate.
The movie industry has already forced BT to block Newzbin 2, a members-only which aggregates illegally copied material.
BT said: "We can confirm we are now in receipt of a letter from the BPI. BT is considering its response."
The telecoms operator added that a court order would be needed before any blocking could begin.
A source told the BBC the firm was unlikely to fight a lengthy legal battle as it had in the Newzbin case.
"We would not tolerate Counterfeits 'R' Us on the High Street - if we want economic growth, we cannot accept illegal rip-off sites on the internet either," said the BPI's chief executive, Geoff Taylor.
Richard Mollet, chief executive of The Publishers Association added: "It is crucial that the creative sector keeps up the momentum of getting internet companies to do their bit in tackling illegal sites."
The Motion Picture Association, independents trade body PACT and the Creative Coalition Campaign also voiced their support.
IllegalThe Pirate Bay was launched in 2003 by a group of friends from Sweden and rapidly became one of the most famous file-sharing sites on the web.
Although it hosts no files itself, it does allow users to search for and get at copyrighted content including movies, games and TV shows.
In April 2009, the Swedish courts found the four founders of the site guilty of helping people circumvent copyright controls.
They ruling was upheld after an appeal in 2010, but the site continues to function.