Innocent people who want to delete their DNA from police databases face a "postcode lottery" over their chances of success, it has been claimed.

New figures revealed huge differences in the way police forces across England and Wales handle requests to remove DNA records by people arrested and cleared.

Some forces refuse to remove any records once a case is closed while others complied with more than 80% of deletion requests.

Conservative shadow immigration minister Damian Green said the huge disparities highlight how the system of holding DNA is in chaos.

He successfully asked the Metropolitan Police to delete his DNA profile after he was arrested as part of a Whitehall leak probe in November 2008.

Mr Green used the Freedom of Information Act to obtain a breakdown of the number of removal requests in the financial year ending in March.

He said: "These figures show that policy towards DNA is a shambles. Some forces almost always give it back to innocent people. Others always refuse.

"Three forces disgracefully refused the request, and one other said it didn't have the figures. This is why we need a new policy which is clear and fair."

The research revealed South Yorkshire Police is most likely to delete DNA, with 83% of requests granted. While other forces, including Cambridge, Gloucestershire and Nottingham, refused to remove any profiles.

Mr Green said he has received many letters from innocent people who are struggling to recover their DNA from police. He has launched an online petition, Return my DNA, to raise awareness of thousands of innocent people whose DNA continues to be held by police.