MANCHESTER United and Manchester City have until tomorrow to tell the FA what happened following Sunday’s derby, with reports of ugly scenes occurring after the match.

United manager Jose Mourinho and City goalkeeper Ederson are reported to have had a confrontation after City’s 2-1 victory, while it is claimed Mourinho had milk and water thrown at him from the away dressing room.

The home side is understood to have taken exception to City’s post-match celebrations and an altercation — involving up to 20 players and staff in the crowded corridor leading to the dressing rooms — is believed to have left City coach Mikel Arteta with a head wound.

Referee Michael Oliver did not witness the scenes.

The incidents occurred after a fiery end to the much-anticipated clash.

An already feverish atmosphere threatened to boil over on the pitch in the closing minutes when United midfielder Ander Herrera was booked for diving in the box after a tackle by City defender Nicolas Otamendi.

Mourinho has complained but most neutral pundits, however, agreed with Oliver’s decision.

City manager Pep Guardiola shot back: “We won because we were better, in all departments.”