Sir Bernard Hogan-Howe cut short an interview to jump into a taxi and arrest a 19-year-old man on suspicion of theft in Tottenham.
The Mayor has questioned a call from the police commissioner for a change in the law to increase the number of ethnic minority recruits.
Commissioner of the Metropolitan Police Service, Sir Bernard Hogan-Howe, fully supports the call from Baroness Lawrence for decisive action
The Commissioner of the Met Police is calling for mandatory drug-testing for all workers. Sir Bernard Hogan-Howe says anyone failing the test and refusing to get help, should face the sack. The full story now from Richard Pallot.
Sir Bernard Hogan-Howe says that drug-testing would help cut the number of users - as the risk of losing your job would act as a deterrent.
– Sir Bernard Hogan-Howe.
"It seems to me we have got to plant in people’s minds something to affect the demand as well as supply. You can think of many occupations where if you were working with a colleague you would want to be sure in fact that they were drug free."
The Commissioner of the Metropolitan Police is calling for mandatory drug-testing at work.
Sir Bernard Hogan-Howe says that anyone failing a drug test and refusing to get help should face the sack.
He wants it to cover all occupations, but the special focus would be on teachers, transport staff and health staff working in intensive care.
The law says workers must consent to being tested, but can face disciplinary action in certain circumstances if they refuse.
London Mayor Boris Johnson and Met Police Commissioner Bernard Hogan-Howe will face tough questions from the London Assembly later over policing in the capital.
It comes after the starting pay for police constables was cut by 4,000 pounds.
Metropolitan Police Commissioner Bernard Hogan-Howe wants to cut all crime. He says as far as he is concerned "all crime matters".
He added: "If we can cut all crime then we will end up with a happier and a more confidant London - a place people want to invest, people want to visit and I'm confidant we can do that in the future".
Metropolitan Police Commissioner Bernard Hogan-Howe believes that stop and search has improved. He says he get "less complaints" than he did. He added that the overall amount of stop and search has been reduced by 40 per cent.
Metropolitan Police Commissioner Bernard Hogan-Howe says the people of London should always expect "high things" of the Met. He said that "where necessary we (should) get rid of the people who are damaging our reputation".
Metropolitan Police Commissioner Bernard Hogan-Howe spoke on the subject of two female police officers killed earlier:
I am deeply shocked and saddened by the death of two officers in Manchester today in this horrific attack. It is a tragic reminder that officers face the potential for danger on a daily basis. My thoughts are with the families and colleagues of these brave police officers.
The Met Commissioner Bernard Hogan-Howe has told the London Assembly that he is confident the Olympics will have proper security. He also explained that the problems at G4S were made worse because the company assumed it had a communication problem and did not realise it was short of staff.
London's top police officer, Commissioner Bernard Hogan-Howe, gave a lesson on the dangers of knife crime to teenagers at Edmonton County School - including the friends of a pupil who was killed last year.