A law firm's list of broadband subscribers suspected of illegally downloading and sharing adult videos online were leaked onto the Internet after the firm's website was hacked.

The personal details, including names and addresses, of more than 5,300 BSkyB Broadband subscribers, together with a list of adult videos they may have downloaded and shared online and 1,000 confidential e-mails, apparently came from the database of the ACS:Law. Hackers then uploaded the list to the file-sharing website, The Pirate Bay.

ACS:Law is known for demanding $792 compensation from online file-sharers who violated music and movie copyrights. Hackers attacked its website in retaliation for its anti-piracy efforts.

The firm has reported the cyber attack to the police, the Information Commissioner's Office and the Solicitors Regulation Authority. The attack is now under investigation.