Detectives are probing torture allegations made against the British-born former head of the security services in Bahrain, Home Secretary Jack Straw has confirmed.

Colonel Ian Henderson has been accused of overseeing the torture of pro-democracy activists there.

Mr Straw told Channel 4 News that an inquiry was now under way.

"I understand that the matters concerned, the allegations, are the subject of an investigation by the Organised Crime branch of the Metropolitan Police," said Mr Straw.

"I'm not in possession of any further information about this man," added Mr Straw, although he did confirm that Col Henderson is a British citizen.

The allegations against Col Henderson have attracted the attention of a variety of human rights groups.

A spokesman for Amnesty International welcomed confirmation that a police inquiry was being undertaken.

"This is the very least we would have wished to see," the spokesman added.

A Metropolitan Police spokeswoman confirmed: "We are in receipt of papers alleging torture.

"These papers are being examined by officers from the Organised Crime Group. We are not discussing the matter further."

Col Henderson, 71, and his wife Marie are known to have spent the New Year period on holiday at a house on Dartmoor in Devon.

They are now thought to have left the country again.

Allegations denied

In a previous interview with Channel 4 News, Col Henderson said the allegations that he had been involved in torture were "laughable".

He claimed that the allegations were invented by opposition groups in Bahrain to attract media attention.

Nevertheless last week Lord Avebury, vice chairman of the Parliamentary Human Rights Group, said he had written to Mr Straw asking for action to be taken against Col Henderson while he was in this country.

There has been a growing movement for the restoration of democracy in Bahrain since the state's rulers abolished the national assembly in 1975.

The security services in Bahrain have been central to the prevention of a return to democracy.

There have been allegations against the secret police that suspects have been murdered, and claims that children have been arrested and maltreated.

Col Henderson, who was born in Aberdeenshire, moved to Bahrain in 1964 after being deported from Kenya after independence.

He was part of the British colonial security apparatus in Kenya suppressing the Mau-Mau uprising led by Jomo Kenyatta.

He spent 30 years directing Bahrain's state security forces before retiring two years ago. He is now an adviser to Bahrain's Ministry of the Interior.