Shoaib Akhtar realised West Ham's match against Millwall was going to be a night to remember – for the worst reasons – when he looked out of his kebab shop window and saw a bloodied fan uprooting a concrete bollard to hurl into a crowd of screaming rivals.

What started as a normal, midweek Carling Cup tie, with Hammers supporters crowding into the take-away 500 metres from the Boleyn Ground before kick-off, had within 10 minutes become what one witness described as a "scene from hell". "These guys looked and behaved like they wanted to kill each other," he added.

The rampage outside Upton Park Tube station on Green Street, the multicultural thoroughfare that leads to the stadium, was merely the opening salvo in nearly six hours of violence inside and outside the ground on Tuesday night. It drew comparisons with the football hooliganism of the 1970s and 1980s, and yesterday prompted allegations that police and officials had dropped their guard for a pre-arranged clash between two sets of fans with a century-long history of mutual hatred and drink-fuelled barbarity.

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With broken glass and pieces of brick still littering the street, Mr Akhtar, 37, said: "It was like someone fired a starting pistol. They were just animals."

Scotland Yard said it was using a specialist team to identify from CCTV footage the perpetrators of the clashes inside and outside the ground. The Football Association promised life bans for anyone involved.

Messages left on websites and chatrooms, apparently by members of notorious hooligan "firms" associated with the two clubs, showed that the tie had been identified as an opportunity for a showdown between the rival groups, whose teams are separated by two divisions and last played each other in 2005. One message advised: "Make sure you bring your bats and don't bring your kids."

Another message posted on Monday on the West Ham fans forum, Bubble Blowers, laid out plans to rendezvous with a hard core of the 2,300-strong Millwall contingent, saying: "Heartfelt message to all concerned. PLEASE be in the right place at the right time tomorrow. No fucking excuses. We can all hang our head in shame if we let any of those cunts even think they can take liberties."

Senior police admitted they were aware of plans for a brawl but insisted they were adequately prepared for the match, which was designated "category five", with the highest risk of hooliganism. Chief Superintendent Steve Wisbey, the officer in charge of policing the game, said the violence was limited to a small number of supporters.

But witnesses found this difficult to square with the events that ultimately required the presence of more than 700 riot police, and whose aftermath left one man stabbed in the chest, 13 people arrested and dozens of fans bloodied and bruised. Among those treated at the scene was a man who was hit in the head with a dart. After the initial skirmish outside the Tube station, splinter groups of supporters roamed surrounding streets looking for a confrontation as the match was being played. A 43-year-old man, reportedly an innocent bystander, was in a stable condition in hospital last night after he was knifed in the chest during these clashes.

In a statement on their official website, West Ham said they were investigating the "appalling events" at the Boleyn Ground to ensure appropriate was action taken as swiftly as possible, with life bans for anyone behind the disturbances. The chief executive, Scott Duxbury, said: "We will leave no stone unturned in identifying the perpetrators, rooting them out and then taking the proper action. The vast majority of people at the game were law-abiding, loyal football fans and a small minority spoiled it for everyone. They will not be allowed to succeed."

But his words fell on deaf ears among some of those involved. Jonny, a Millwall supporter who said he saw the violence but did not take part, told The Independent: "I'm delighted. The best thing that came out of last night was the reignition of the hatred between us. Shame it can't be like that every week."

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