A West Yorkshire MP has said the Prime Minister needs to "show some leadership and judgment" over the Andrew Mitchell incident.
Yvette Cooper, Labour's Shadow Home Secretary, said David Cameron should make Mr Mitchell stand down as Chief Whip "straight away".
It follows claims he called police officers "plebs" after they made him wheel his bike out of Downing Street's pedestrian exit instead of opening the main gate.
He has apologised to the officers but has denied using the word "plebs".
Defence Secretary Phillip Hammond said the row had been "hijacked".
– Yvette Cooper MP (Labour, Normanton, Pontefract and Castleford)
We urged David Cameron and Andrew Mitchell to properly deal with this incident from the start. Instead the drawn out saga of half apology and oblique denial has left a cloud hanging over the Government's attitude to public servants.
It is now very hard for the Chief Whip to command respect in Parliament or beyond.
The Prime Minister needs now to show some leadership and judgement and take seriously the message this incident has sent to people across the country about his Government. He needs to end this now and make Andrew Mitchell stand down as Chief Whip straight away.