Bottles and missiles from a building site were hurled at police and officers were spat at during the United-Reading game at the Kassam Stadium on September 24 last year.

Police have tracked down eight of the 13 troublemakers, and are today appealing to Oxford Mail readers to help catch the remaining five, who are believed to be Oxford fans.

Six people were arrested. Two were convicted of threatening behaviour and banned from attending British or international matches for three years. Four are awaiting trial.

Police were left searching for seven more. Two have since been identified.

Pc Simon Feist, Oxford's football liaison officer, who is leading the investigation, said: "These individuals are ruining the good reputation of the game here in Oxford, destroying the game for supporters who enjoy coming to the match as a family, while also posing a threat to genuine fans and police alike.They were intent on causing disorder at the September fixture and need to be identified.

"The offences they are involved in are serious. In once incident a bottle was thrown at an officer, striking him on the head.

"Fortunately, he was not injured, but it could have been more serious.

"One offender repeatedly spat at the officers who were trying to calm down a situation in the bar area of the north stand and were not in a position to deal with him for the offence."

Plain-clothes police have been to all United matches since the trouble, and pictures have been circulated to intelligence sources in Oxford.

Stadium manager Tony Ashley said: "The majority of the incidents happened outside the stadium because of the CCTV coverage we have inside.

"We do examine CCTV footage of any incidents as a club, and applaud Thames Valley Police for persevering in identifying these offenders."

Trevor Lambert, secretary of OxVox, the club's supporters' trust, said: "We do not wish to see hooliganism tolerated and support moves that bring thugs to court."

Anyone who knows the alleged offenders can call Pc Feist on 08458 505505 or Crimestoppers free and anonymously on 0800 555111.

Yesterday, 2,000 known football thugs were banned from attending Euro 2004 in Portugal this summer, 14 of whom are from Oxfordshire. Four more could be banned before the tournament.