Downing Street says no investigation will be carried out into the conduct of Chief Whip Andrew Mitchell.
It follows a letter requesting such an investigation from Yvette Cooper, the MP for Normanton, Pontefract and Castleford.
There were calls for Andrew Mitchell to resign after shouting at police officers when they refused to let him take his bicycle through the main gates at Downing Street. He has since apologised for his behaviour, but denies reports he called them "plebs".
The Secretary of the Cabinet, Sir Jeremy Heywood, has responded saying: