Mayor on Quick's resignation

Britain's most senior counter-terrorism officer has resigned after inadvertently revealing details of a highly secret police operation.

Mayor of London Boris Johnson said live on the BBC's Today programme that it was "with great sadness" that he had accepted Assistant Commissioner Bob Quick's resignation.

Police had brought forward raids after Mr Quick revealed secret papers to photographers when arriving at No 10.

Twelve men are in custody after raids in north-west England.