The senior civil servant who left government documents detailing intelligence on al-Qaeda on a commuter train in June has pleaded guilty to a breach of the Official Secrets Act.
Richard Jackson, 37, of Yately in Hampshire, appeared before City of Westminster magistrates.
The court heard the loss "had the potential to damage national security and UK international relations". Jackson had taken the documents home inadvertently and was "physically sick" when he realised what had happened, The Guardian reports.
Jackson was fined £2,500 and must pay £250 costs, according to the Beeb.
He spent most of the hearing with his head in his hands. The civil servant faced a maximum sentence of three month imprisonment.
The documents, one of which was entitled "Al-Qaeda vulnerabilities", were found on June 10 by one of Jackson's fellow passengers on a Surrey service from Waterloo. The passenger gave the orange folder containing the documents to the BBC, which handed it to the Metropolitan Police.
Jackson, a Ministry of Defence employee, was on secondment to the Cabinet Office at the time of the incident. Many observers were surprised when the decision to prosecute rather than deal with the blunder internally was revealed in late September. ®