The MPA has started legal action against the ISP in a bid to ensure it uses Cleanfeed technology, which BT already supplies to a number of smaller ISPs, to prevent web users visiting Newzbin, a site that offers links to other locations on the web where music, movies and other content can be illegally downloaded. The technology is already used to block access to websites containing child sex abuse images.
MPA initially started legal action against the site in 2010, and subsequently Newzbin was required to remove any material that infringed copyrights. However, the site went into administration and was then sold to new owners and launched again from the Seychelles.
"Newzbin has no regard for UK law and it is unacceptable that it continues to infringe copyright on a massive and commercial scale when it has been ordered to stop by the High Court," said Chris Marcich, European president of the MPA.
"We have explored every route to get Newzbin to take down the infringing material and are left with no option but to challenge this in the courts."
The MPA said it was targeting BT first as it's the UK's largest ISP, with 5.6 million subscribers.
BT confirmed it would "be appearing in court, following an application for an injunction by members of the MPA" but said it had "no further comment to make at this stage".