A major gas leak in central London forced the closure of Charing Cross train station and the evacuation of hundreds of people from nearby nightclubs and hotels on Tuesday.

Police closed the Strand, a major road artery that leads into Trafalgar Square - the very heart of the capital city - and advised people to avoid the area.

The fire brigade said it was called at 2 am and was dealing with a ruptured gas main emitting "high levels of natural gas". Some 20 firefighters were at the scene.

The emergency prompted police to evacuate 1,450 people from hotels and the Heaven nightclub.

"Please avoid the area and find alternate travel routes," the London Fire Brigade said.

The railway operator said Charing Cross and Waterloo East stations would remain closed, with some services diverted to other stations and others likely to be cancelled. Services were expected to resume by noon, operator Southeastern said.