A palmtop MI5 computer believed to contain information on terrorism has been stolen from a house in Greater Manchester.

A burglar took the device from the open window of a building hired by the security service in an apparently opportunist theft. It is believed that files on the palmtop were encrypted.

A spokesman for Greater Manchester Police said: "An encrypted handheld computer was stolen. It is believed the offender entered through an open window. "

Earlier this week, it emerged that police were investigating the sale of a camera on eBay which is said to have contained MI6 images of terror suspects.

And in June an officer working for the security services was suspended after leaving top secret files on terrorism on a train.

The Ministry of Defence recently admitted losing 658 laptops since 2004. The department is undergoing a wide-ranging review of security which involves encrypting laptops and improving data handling processes as a response to the Burton Review (PDF).