The bitter and bloody rivalry between West Ham and Millwall supporters is one of the oldest, most intense feuds in the history of British football.
Both teams were created in the industrial heartland of east London in the late 19th century by rival factory workers.
Millwall FC was formed in 1885 by labourers at JT Morton's canned food factory on the Isle of Dogs. Ten years later, a foreman at Thames Ironworks, London's last major shipbuilding firm, decided to form a football team to improve the morale of his workers.
The two sides frequently played each other in heated local derbies.
At start of the 1906/07 season, a particularly ferocious encounter saw one player hurled against a metal advertising board. Millwall finished the game with only nine men, after the others were stretchered off following heavy tackles.
The East Ham Echo reported: "From the very first kick it was seen that there was likely to be some trouble. All attempts at football were ignored." The supporters were also criticised for fighting each other in the stands.
In 1926, when tough economic times were taking their toll on the docks, the rivalry turned nasty. The General Strike of that year was observed by workers in the East End, who were mainly West Ham supporters, but the Millwall-supporting shipyard workers of the Isle of Dogs refused to lend their support, provoking mass outrage.
The bitterness of this betrayal would endure for years.
In the 1960s, the two sides were again divided, this time by the arrival of London's two most notorious gangster families, the Krays and the Richardsons. The former were born and bred in the East End and supported West Ham, the latter were from south of the river and followed Millwall.
In 1972, a testimonial for Millwall defender Harry Cripps was marred by intense fighting between the two club's "firms": groups of hooligans intent on violence.
Four years later, a Millwall supporter died at New Cross station after falling out of a train during a fight with West Ham fans.
Leaflets were later distributed at Millwall's home matches bearing the words: "A West Ham fan must die to avenge him".