A mass brawl between Millwall and Everton fans was “some of the most shocking football violence seen for some time”, a senior Met Police officer has said.
Rival supporters clashed before Saturday’s FA Cup tie between the two sides, with one man slashed across the face with a knife.
An officer was also injured and the Met said a number of coaches carrying Everton fans had been damaged.
No arrests have yet been made.
Trouble between fans started in the Hawkstone Road area of Southwark, near to Millwall’s stadium The Den.
Both the police officer and the injured fan have been discharged from hospital, but the man is said to have a “life-changing” scar to his face.
Deputy Assistant Commissioner Matt Twist praised the efforts of his officers, saying their actions “prevented the violence from escalating”.
He said: “Their determination in restoring order was outstanding, despite furniture, bottles and glass being launched at them as they attempted to disperse the crowd.”
Video footage is being analysed by officers in an attempt to identify dozens of people involved in the violence.
Mr Twist said: “We will use this evidence and all of the tools within our power to locate the individuals involved in this ridiculous behaviour whether they come from London, Liverpool or elsewhere.
“We will bring them to justice.”
Because the violence happened outside Millwall’s stadium the Football Association said it would not be investigating.
The match, which Millwall won 3-2, was also marred by allegations of racist chanting.