Mark Jelley pleaded guilty to assaulting a constable when he appeared at Mansfield Magistrates’ Court on Wednesday.
Jelley, 20 saw his friend being detained by the officer in Mansfield town centre in the early hours of September 13.
He said he had been ‘in drink’ when he decided to intervene. He admitted pushing the officer over onto the ground. The policeman who had not been hurt in the incident was crouching on the floor ‘off balance’.
Jelley was fined £140 with £150 criminal court charge, £85 costs and £50 compensation.