A politics lecturer has been fined £475 for assaulting a police officer during a student protest in Manchester.
Dr Emmanuel Guittet said he was keeping the peace in a scuffle between police and demonstrators at the tuition fee protest on 30 November 2010.
But a police officer told Manchester Magistrates' Court the lecturer punched him and twisted his arm.
District Judge Wendy Lloyd fined the University of Manchester lecturer £400 and ordered him to pay the officer £75.
The academic, who specialises in terrorism and political violence at the University of Manchester, told the court that he was acting as a peacekeeper when demonstrators clashed outside the Jean MacFarlane Building on Oxford Road.
He claimed he was pushed and assaulted by police.
But Pc Gary McCarthy claimed that it was Guittet who turned aggressive, lashing out, punching him and grabbing his thumb and twisting his arm.
Dr Guittet, who denied assault, was convicted on Friday.