The origins of West Ham's links with organised football-related violence starts in the 1960s with the establishment of The Mile End Mob (named after an area of the East End of London).^[163] During the 1970s and '80s (the main era for organised football-related violence), West Ham gained further notoriety for the levels of hooliganism in their fan base and antagonistic behaviour towards both their own and rival fans, and the police. During the '70s in particular, rival groups of West Ham fans from neighbouring areas often did battle with each other at games, most often groups from the neighbouring districts of Barking and Dagenham.^[164]

The Inter City Firm were one of the first "casuals", so called because they avoided police supervision by not wearing football-related clothing and travelled to away matches on regular InterCity trains, rather than on the cheap and more tightly policed "football special" charter trains. The group were an infamous West Ham-aligned gang. As the firm's moniker "inter city" suggests violent activities were not confined to local derbies – the hooligans were content to cause trouble at any game, though nearby teams often bore the brunt.^[164]

The 2005 independent film Green Street starring Elijah Wood and Charlie Hunnam focuses on a firm of West Ham hooligans.^[165]