An urgent inquiry is under way into how an MI6 officer mislaid a laptop computer containing classified material.

The incident was revealed days after the news that an MI5 laptop computer with classified information on Northern Ireland was stolen at a London Underground station.

The Foreign Office has confirmed that the MI6 laptop was lost on 3 March.

The incident was reported to the Metropolitan Police and following a police investigation, the computer was recovered on 16 March.

"We were assured by the police that the laptop was not compromised," a Foreign Office spokeswoman said.

She added: "It largely held training information - it was not something hugely damaging."

Incident report

The spokeswoman said Foreign Secretary Robin Cook had been kept informed.

The Foreign Office, which has departmental responsibility for MI6 - formally known as the Secret Intelligence Service - is preparing a report on the incident.

It will be sent to the Parliamentary Intelligence and Security Committee, the body chaired by former Defence Secretary Tom King, which oversees the work of the intelligence agencies.

Mr King has already called for a report into the previous incident involving the MI5 computer.

The new incident will add to the intelligence community's embarrassment.

Anonymous advert

The Sun said that the MI6 officer lost the laptop in a taxi after drinking at a tapas bar near MI6's headquarters on the south bank of the Thames.

It claimed that the service placed an anonymous advertisement in a newspaper offering a "substantial reward" in a bid to get the laptop back.

The Sun said the advert read: "Academic urgently seeks information leading to the recovery of PhD vital research notes stored on Toshiba 4000 Series CDS laptop computer in black carrying case lost in London on evening 3 March 00."

The Foreign Office spokeswoman said she could not discuss the circumstances of the laptop's loss, nor say whether the MI6 employee involved would face disciplinary action.