Geoff Taylor, the chief of UK record industry trade body the BPI said in a statement, "Establishing partnerships with ISPs is the number one issue for the BPI, and we are beginning to form positive working relationships with BT, Virgin Media and most of the other major ISPs."
It was still unclear whether BT has signed on to the so-called "three strikes" procedure agreed upon by the record industry and the government. Accused users will get two warnings for infringing music copyright and the third strike will be disconnection from the Internet.
Taylor added, "Everyone agrees on where we need to be, and we are working closely with our colleagues across the music community, the more progressive ISPs, and government to get us there."
BT did not comment but did say if the BPI provides evidence against BT broadband customers, those customers can expect similar threatening letters.
You can read the full BT letter here.