Ever since the climax of the Manchester derby on Sunday, everyone has been talking about the bust-up inside the Old Trafford tunnel rather than the result itself.

Of course, Man City would win the game 2-1 thanks to goals from Nicolas Otamendi and David Silva, capitalising on two Romelu Lukaku errors.

United's reply came through local lad Marcus Rashford, but boss Jose Mourinho was aggrieved that the home side weren't awarded a penalty for an apparent foul on Ander Herrera late in the game.

In fact, the Spaniard was adjudged to have dived in search of a penalty and received a yellow card for his troubles.

Following the game, wild celebrations sparked inside the visitors dressing room and would eventually spill out into the tunnel, something United boss Mourinho took great exception to.

From there, plenty of stories have emerged suggesting all kinds of things. Namely, Romelu Lukaku threw a drink at Mikel Arteta, causing the City coach a gash on his face, a member of City's staff insulted Zlatan Ibrahimovic while Ederson and Jose Mourinho got extremely heated with one another.

How much of those stories, if any of them, are true is still up for debate but it seems that however exaggerated events may have become, something definitely went down.

Yesterday, the Football Association went in search of answers for what occurred in the tunnel: “The FA have sought observations from both clubs in relation to an incident which occurred following yesterday’s game."

United and City have been given until 6pm on Wednesday to respond to the FA, after which the governing body will decide whether the situation demands further investigation and potential sanctions for both clubs.

If even half the stories of the fracas are true, then both clubs could face serious repercussions for their actions, but according to The Times, they look set to avoid them.

The report states that there is no CCTV in the Old Trafford tunnel, quite bizarrely, and any investigation would rest on Man United's word against Man City's.

Of course, that's no foundation for any kind of case and with zero eye-witnesses - conveniently - or accounts from the officials to use, the FA are pretty powerless on this one.