Football hooliganism is unruly, violent, and destructive behaviour by overzealous supporters of association football clubs, including brawling, vandalism and intimidation.
Football hooliganism normally involves conflict between gangs, often known as football firms (the term derives from the British slang for a criminal gang), formed for the specific purpose of intimidating and physically attacking supporters of other teams. Other terms commonly used in connection with hooligan firms include “army”, “boys”, “casuals”, and “crew”. Certain clubs have long-standing rivalries with other clubs (usually, but not always, geographically close) and hooliganism associated with matches between them (sometimes called local derbies), is likely to be more severe.
Conflict may take place before, during or after matches. Participants often select locations away from stadia to avoid arrest by the police, but conflict can also erupt spontaneously inside the stadium or in the surrounding streets. In such cases, shop windows may be smashed, rubbish bins set on fire, and police cars may be overturned. In extreme cases, hooligans, police, and bystanders have been killed, and body-armoured riot police have intervened with tear gas, police dogs, armoured vehicles and water cannons. Hooligan-led violence has been called “aggro” (short for “aggravation”) and “bovver” (the Cockney pronunciation of “bother”, i.e. trouble). To “run” opposing hooligans is to make them flee.