Police commisioner has said there were '4 small explosions.' Three at tubes and one on a bus. They are saying it appears that the detonators rather than the bombs exploded.

Londoners urged to 'stay where they are.'

One man arrested in last 20mins in Whitehall just outside Downing St, chased and on the ground, surrounded by armed police.

UCH (university college hospital) nr Warren St tube cordoned off. Only one injury reported and it is thought it is the man carrying one of the nail bombs. His back pack exploded and he may have gone to UCH for treatment. Not known if he has been found in the hospital.

London on 'Amber Alert' - the highest alert status. Confusion around 'bombs', as in what went wrong, why didn't they explode , were they dummy bombs with live detonators, is it linked to last bombings or a strange hoax.