Football hooliganism is defined as unruly and destructive behaviour — brawls, vandalism and intimidation — by association football club fans. Fights between supporters of rival teams may take place before or after football matches at pre-arranged locations away from stadiums, in order to avoid arrests by the police, or they can erupt spontaneously at the stadium or in the surrounding streets. Football hooliganism ranges from shouts and fistfights to riots in which firms clash with bats, bottles, rocks, knives or guns. In some cases, stadium brawls have caused fans to flee in panic; some being killed when fences or walls collapsed. In the most extreme cases, hooligans, police, and bystanders have been killed, and riot police have intervened with tear gas, armoured vehicles and water cannons.

A football firm (also known as a hooligan firm) is a gang formed to fight with supporters of other clubs. Some firms, especially in southern and eastern Europe, have been linked with far right politics or racism, other firms have been associated with leftist politics or anti-racism. The firms' political views are not representative of all supporters of the teams. In the 1970s and early 1980s, the casual subculture transformed the British football hooliganism scene. Instead of wearing working class skinhead-style clothes, which readily identified hooligans to the police, firm members began wearing designer clothes and expensive offhand sportswear.

Football hooliganism has been depicted in films such as: I.D., The Firm, Cass, The Football Factory, and Green Street (see below). Some critics argue that these media representations glamorise violence and the hooligan lifestyle.

Football hooliganism in England dates back to the 1880s, when what were termed as roughs caused trouble at football matches. Local derby matches would usually have the worst trouble, but in an era when travelling fans were not common, roughs would sometimes attack the referees and the away team's players. Between the two World Wars, football hooliganism diminished to a great extent, and it started to attract media attention in the early 1960s. A moral panic developed because of increased crime rates among juveniles, and because of the mods and rockers conflict. Football matches started to feature regular fights among fans, and the emergence of more organised hooliganism. Fans started to form themselves into groups, mostly drawn from local working class areas. They tended to all stand together, usually at the goal-end terrace of their home football ground, which they began to identify as their territory. The development of these ends helped bring about national gang rivalries, focused primarily around football clubs. With the growth of fans travelling to watch their local club play away matches, these gangs became known as hooligan firms, and during matches they focused their attentions on intimidating opposing fans. Some hooligans travelled to games on the Football Specials train services.

Starting in the late 1960s in the United Kingdom, the skinhead and suedehead styles were popular among football hooligans. Eventually, the police started cracking down on people wearing typical skinhead clothing styles, so some hooligans changed their image. In the early 1980s, many British hooligans started wearing expensive European designer clothing, to avoid attracting the attention of authorities. This led to the development of the casual subculture. Clothing lines popular with British casuals have included: Pringle, Fred Perry, Le Coq Sportif, Aquascutum, Burberry, Lacoste, Timberland, Lonsdale, Sergio Tacchini, Ben Sherman, Ralph Lauren, Abercrombie and Fitch and Stone Island.

During the 1970s, organised hooligan firms started to emerge with clubs such as Arsenal (Gooners, Herd) Birmingham City (Zulus), Derby County (Derby Lunatic Fringe), Chelsea (Headhunters), Everton FC (County Road Cutters), Leeds United (Leeds Service Crew), Southampton FC (The Deceased Crew),QPR (C Mob,Ellerslie Enders), Burnley FC (The Suicide Squad), Liverpool FC (The Urchins), Manchester City (Guvnors, Young Guvnors, Mayne Line Service Crew) Manchester United (Red Army), Portsmouth (6.57 Crew), Sheffield United (Blades Business Crew) and West Ham United (Inter City Firm). Lower league clubs also had firms, such as Blackpool's Rammy Arms Crew and Millwall's (F-Troop). Click on the links to learn more about the groups - and note that whilst the football team badges are used for identification purposes, these 'firms' do not in any way represent any values of the respective football teams.

Two main events in 1973 led to introduction of crowd segregation and fencing at football grounds in England.Manchester United were relegated to the Second Division, and the Red Army caused mayhem at grounds up and down the country, and a Bolton Wanderers fan stabbed a young Blackpool fan to death behind the Kop at Bloomfield Road during a Second Division match.

In March 1985, hooligans who had attached themselves to Millwall were involved in large-scale rioting at Luton when Millwall played Luton Town in the quarter final of the FA Cup. Prime Minister Margaret Thatcher's immediate response was to set up a "War Cabinet" to combat football hooliganism. On 29 May 1985, 39 Juventus fans were crushed to death during the European Cup Final between Liverpool and Juventus at Heysel Stadium in Brussels; an event that became known as the Heysel Stadium disaster. Just before kick-off, Liverpool fans broke through a line of police officers and ran toward the Juventus supporters in a section of the ground containing both English and Italian fans. When a fence separating them from the Juventus fans was broken through, the English supporters attacked the Italian fans, the majority of whom were families rather than ultras who were situated in the other end of the ground. Many Italians tried to escape the fighting, and a wall collapsed on them. As a result of the Heysel Stadium disaster, English clubs were banned from all European competitions until 1990, with Liverpool banned for an additional year.

On 11 May 1985 a 14-year-old boy died at St Andrews stadium when fans were pushed onto a wall by Police which subsequently collapsed following crowd violence at a match between Birmingham City and Leeds United. The fighting that day was described by Justice Popplewell, during the Popplewell Committee investigation into football in 1985 as more like "the Battle of Agincourt than a football match". Because of the other events in 1986 and the growing rise in football hooliganism during the early 1980s, an interim report from the committee stated that "football may not be able to continue in its present form much longer" unless hooliganism was reduced, perhaps by excluding "away" fans.

Margaret Thatcher, UK Prime Minister from 1979 to 1990, made a high-profile public call for the country's football hooligans to be given "stiff" prison sentences to act as a deterrent to others in a bid to clamp down on hooliganism. Her minister for sport, Colin Moynihan, attempted to bring in an ID card scheme for football supporters.

The government acted after the Hillsborough disaster in 1989, when 96 fans died, bringing in the Football Spectators Act 1989 in the wake of the Taylor Report. However, the Hillsborough Justice Campaign states: "the British Judicial system has consistently found that violence or hooliganism played no part whatsoever in the disaster". On 15 February, 1995, England played Ireland. English fans started to throw items down into the stand below and rip up seats; after battles broke out between police and English fans, 50 people were injured. Rumours of IRA retribution at Dublin Airport never materialised and no fixture has been arranged between the two neighbouring countries since.

English and German fans have a rivalry dating back to the late 1980s. Other occasional clashes have occurred with a few other teams since the mid 1980s. France 98 was marred by violence as English fans clashed with the North African locals of Marseille, which led to up to 100 fans being arrested.

In the 2000s, English football hooligans often wear either clothing styles that are stereotypically associated with the "[casual]" subculture, such as items made by Shark and Burberry. Prada and Burberry withdrew certain garments over fears that their brands were becoming linked with hooliganism. English hooligans have begun using Internet forums, mobile phones and text messages to set up fight meetings or provoke rival gangs into brawls. Sometimes fight participants post live commentaries on the Internet.

Football violence in British stadiums declined after the introduction of the Football Spectators Act, and in the 2000s much of the trouble occurred away from stadiums or away at major international tournaments. At Euro 2000, the England team was threatened with expulsion from the tournament, due to the poor behaviour of the fans. Following good behaviour in the Korea-Japan 2002 and Portugal 2004, the English reputation has improved. At the 2006 FIFA World Cup in Germany, there were limited incidences of violence, with over 200 preventative arrests in Stuttgart (with only three people being charged with criminal offences) 400 others taken into preventative custody. During that day, Police believe that on average each rioter consumed or threw 17 litres of beer.

Despite hooliganism declining domestically, death threats by English hooligans have become more common in the 2000s. Rio Ferdinand was the target of death threats from Leeds United fans, as was Peter Ridsdale. Swedish referee Anders Frisk quit his position after receiving death threats from Chelsea F.C. fans. Reading players Ibrahima Sonko and Stephen Hunt also received death threats from Chelsea fans in 2006. A steward died after serious clashes between firms from Aston Villa and Queens Park Rangers after a Carling Cup game in September 2004. It has been documented that most English hooligans are in their late teens or early twenties, although it is not uncommon for older hooligans to take part, usually as leaders. They usually come from working class backgrounds, mainly employed in manual or lower clerical occupations, or (to a lesser extent) are working in the grey market or are unemployed