Andrew Mitchell faces a fresh ordeal at the hands of Labour and Tory backbenchers today as he struggles to cling on to his job.

The Chief Whip is set for intense barracking when he attends Prime Minister's Questions for the first time since his notorious confrontation with police last month.

A few hours later, the powerful Conservative 1922 Committee will consider Mr Mitchell's prospects for survival, amid signs that support within the party is ebbing away.

The Sutton Coldfield MP remains under pressure over his tirade at police who refused to let him cycle through the main gates at Downing Street.

He has denied calling the officers "plebs", but apologised for swearing and not showing enough respect.

Labour leader Ed Miliband could seek to capitalise on the continuing row by challenging David Cameron on the issue in the Commons this afternoon.

The party is tabling a motion calling for Mr Mitchell to be docked £1,000 from his salary - roughly the same amount he could have been fined for swearing at an officer.

However, the real test is likely to come this evening when the 1922 committee of Tory backbenchers gathers.

The Prime Minister has reiterated his backing for Mr Mitchell, who was only appointed in last month's reshuffle, but some MPs question his ability to enforce discipline in the wake of the controversy.

Mr Mitchell will not be attending the session, but it is understood he will meet members of the committee's executive afterwards.