Microsoft has moved to clamp down on software pirates in the UK after discovering what it describes as a large volume of high quality counterfeit versions of Windows XP.

Kicking off its Windows XP Counterfeit Project, the software giant has invited "anyone unsure as to the legitimacy of their Windows XP software" to submit their products for analysis.

Software that is found to be counterfeit will be replaced for free subject to the terms and conditions of its offer, Microsoft promised.

"This is a great opportunity for users to confirm the authenticity of Windows XP software whilst helping gather vital information about illegal traders," said Alex Hilton, licence compliance manager at Microsoft.

"Illegal software is a risk to users as it is less dependable, less secure and unsupported. I would urge anyone who has suspicions to submit their Windows XP software for testing today."

The XP Counterfeit Project marks the latest in a series of moves by Microsoft to target software pirates.

The scheme will allow it to collate intelligence quickly, according to the firm, and help it to "act decisively" against illegal traders and other systematic abusers.

David Frost, director general of the British Chambers of Commerce, said: "It is important that users ensure they are legally licensed to avoid the risks of purchasing and using counterfeit products."