Fire broke out on the top floor of a historic cancer hospital in west London on Wednesday, forcing the evacuation of patients, the fire brigade said.

There were no immediate reports of casualties.

Huge plumes of black smoke issued from the roof of the Royal Marsden Hospital in Chelsea, the first dedicated cancer hospital in the world.

Patients were led from the building, and several of them were placed in an ambulance area in a nearby street, where they were being attended to by nurses who covered them with extra blankets.