A handheld computer containing secret intelligence documents about terrorism has been stolen through the open window of an MI5 hideout, in a fresh data embarrassment.

A burglar who climbed into the property in Greater Manchester on Sunday night got away with the terminal which contained highly sensitive information about national security.

The house was being rented by the national intelligence service but the device was encrypted, so a security breach is thought unlikely.

A spokesman for Greater Manchester Police said: “Shortly after 11.20pm police Sunday 28th September were called to a house in Greater Manchester, following reports of a burglary.

“An encrypted handheld computer was stolen. It is believed the offender entered through an open window. Inquiries are ongoing.”

He asked anyone who was offered the stolen property to hand it in to the nearest police station. Police sources told Times Online that it is believed to be an opportunistic rather than targeted burglary.

The security services and the government have been hit by a number of security breaches in the last year.

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

The new owner, who paid £17 for the camera, found the secret images when he downloaded his own holiday snaps.

There were photos of terror suspects, their names and also fingerprints, according to reports.

Beforehand, in June, the security services suffered another embarrassment when top secret files on the al-Qaeda threat and Iraqi security forces were left on a train in London by an intelligence officer.

The files were handed in to the BBC and returned to the security services. The officer has since been suspended and is facing criminal prosecution.

Last month, it emerged that personal details of up to 50,000 current and former soldiers had gone missing after the loss of three portable hard drives at RAF Innsworth in Gloucestershire.

The Ministry of Defence also faced ridicule after admitting 658 of its laptop computers had been stolen over the past four years.

But the biggest data bungle came last November when two data discs containing the personal details of 25 million parents and their children were lost by HM Revenue and Customs.

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