From Notting Hill carnival-goers and football matches to M25 raves and violent riots, what do we know about the madness of the multitude? Also, Lisa Mueller, Associate Professor of Political Science at Macalaster College, Minnesota, asks why protests succeed or fail. Examining data from 97 protests, she finds that more cohesive crowds are key. Drilling down into two British protests, Occupy London and Take Back Parliament, protesters who united around a common goal won more concessions than ones with multiple aims.

Producer: Jayne Egerton