Man armed with fake gun held in Downing Street

A man with a replica firearm was arrested outside the gates of Downing Street last night.

He was detained at the back entrance of the Prime Minister's official residence on Horseguards Parade after 8pm.

Gordon and Sarah Brown were not there at the time because they were attending a TUC farewell party to Tony Blair. It is possible, however, that their two young sons John and Fraser were at home with their nanny.

The incident is believed to be the first threat to Downing Street involving a firearm, although it is not clear if the replica had been converted to allow it to fire live ammunition.

In February 1991, during John Major's premiership, the IRA exposed the vulnerability of Downing Street in a mortar attack which blew out windows as the Cabinet was in session.

Last month a drug addict and his girlfriend managed to get within yards of the Prime Minister's residence after walking in off the street into the Cabinet Office.