There has been an explosion in central London at the headquarters of Britain's secret service, MI6. The blast happened a few minutes before 10pm. The area at Vauxhall Cross on the banks of the River Thames has been sealed off. So far it is thought that there are no serious casualties.

Witnesses say there were two explosions followed by a cloud of white smoke. It is still not clear whether or not the blast came from inside the building which houses Britain's security service MI6. The building has now been evacuated. It is only a few hundred yards from the headquarters of London's fire brigade. Firefighters say they were called to the scene at Vauxhall Cross in Central London at 9.52pm.

There are at least eight fire brigade units there as well as ambulances and there is now a wide cordon around the area as police search for further devices. The building is on the banks of the River Thames and police river launches are using powerful searchlights trained on the building to search for any damage.