This study examined the collective behaviour of the police during a football match at the 2006 Football World Cup. What peacekeeping and aggravating processes could be identified and what were their consequences? Data were collected using observation and field interviews. Some critical situations could have escalated into riots; however, the police showed trust in the majority of the supporters' intentions to be peaceful. Distrust was reserved for selected individuals who were under surveillance. This, together with tactics involving using different forces for different tasks and an overall organisational strategy focusing on the festivity of the event, was the main reason for the peaceful outcome. A friendly but firm approach was successful in keeping the peace. Copyright © 2012 John Wiley & Sons, Ltd.