Michael Gove, the Secretary of State for Education, said Tory Chief Whip Andrew Mitchell resigned due to "a moment of exasperation" in his row with a police officer.
David Cameron admits it 'became apparent' to the former Chief Whip that he could no longer do his job. So why was it not apparent to the PM?
Government Chief Whip Andrew Mitchell has resigned after swearing at police guarding Downing Street.
Losing one's temper with a police officer would be excusable in most people, but for the Tory chief whip to do means so much more.