Microsoft has been fined $388m (£264m ) for infringing patents held by small US-based anti-piracy vendor Uniloc.

Uniloc first brought a case against the software giant in 2003, claiming parts of Windows XP and Office infringed its patents for generating unique identities for licensed users to prevent the unauthorised use or copying of software.

The award is one of the largest ever in a patent dispute.

The verdict, reached by a jury in a Rhode Island federal court, is part of a long-running dispute.

In August 2008, a federal judge ordered the lawsuit to go to trial in Rhode Island, after Uniloc had successfully appealed against a summary judgement in Microsoft's favour.

Microsoft said it plans to appeal against the verdict.