Gategate: Arresting Andrew Mitchell would have been 'common sense' says Boris Johnson

Johnson has stirred up a hornet's nest by backing the calls for Mitchell to be arrested for his tirade.

"If I read the papers correctly there was a proposal to arrest Mr Mitchell for what he said. That seems to be wholly common-sensical."

"The public order act does allow for police officers' discretion in this matter. They've obviously decided not to go ahead with it. But it shows the gravity of this offence." said Boris.

Tory chief whip Mitchell is recorded as saying "Best you learn your f***ing place... you don’t run this f***ing government... You’re f***ing plebs," he told police officers guarding a gate at Downing Street, according to police records.

The video below shows Johnson's previous statement at the 2011 Conservative Party conference, where he tells Conservative party members that police should show "zero tolerance" to people who swear at them.