ESSEX Police has launched an investigation after a Southend United fan appeared to run across the pitch to assault rival Colchester United supporters during the Essex derby.

The incident happened towards the end of the League One encounter at Roots Hall which Southend won 3-0.

Video images appear to show the Blues fan run across the pitch from the West Stand towards the North Stand where more than 1,000 U's supporters were gathered.

Essex Police's dedicated football officers for both Southend United and Colchester United have vowed the incident will be investigated.

"A post-match investigation will be launched following today's events," said Colchester United football officer PC Niki Howard.

"Myself, Southend United's police football officer and Essex Police cannot be held responsible for the unacceptable actions of a minority.

"We will, however, do everything we can to identify those responsible and ensure they won't cause problems at football again."

The Essex derby was a dramatic affair on and off the pitch.

Colchester United midfielder Alex Gilbey was sent off in the first half for a fierce challenge on Ryan Leonard.

Southend then scored three goals in the final 10 minutes to turn up the atmosphere in Roots Hall.

Blues manager Phil Brown said: “It’s been a great day for us but it’s been saddened by the fracas in the far corner. That’s not something we advocate at the football club. The exuberance from the supporters spilled over because we were winning. It could have been an ugly scene but the stewards did well.”

Steve Kavanagh, chief executive of Southend United, added: “What happened at the game was completely unacceptable and something which does not represent supporters of Southend United. I’m sure the majority of fans will join me in condemning the incident. We will be working with the authorities and will be taking appropriate action.”