It could take less than two weeks for the FA to finish their investigation into what went on in the Stadium of Light tunnel during Sunderland and Oxford United’s fiery clash on Good Friday.

That is according to the ex-head of the PGMOL Keith Hackett, speaking exclusively to Football Insider about the incident that overshadowed the Black Cats 3-1 win over Oxford.

Karl Robinson alleges his goalkeeper Jack Stevens was headbutted in the tunnel during the interval.

The U’s boss revealed on Monday he is yet to hear whether the FA take action and Hackett insisted he may have to wait a fortnight.

He told Football Insider correspondent Connor Whitley: “There’s an alleged confrontation in the tunnel. The tunnel’s wide enough at Sunderland for this to happen.

“The arrangement that I had was quite clear, we had a few of these in my time. We decided that the fourth official would go to the tunnel, rather than go to the centre of the pitch and get together. At half-time and full-time he’d head to the tunnel and stand at the head with a good view of the players coming towards him. If there’s an outburst he can handle it or prevent it and he’s there to report.

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“In that situation, he’ll have seen it, the point I was pushing for was cameras in the tunnel. There’s a reluctance for cameras in the tunnel.

“The outcome is, this particular situation will be reported to the FA, for sure in their incident report.

“That’s all communicated by email, there’s no waiting for the post like in my day. Almost within an hour of the game, it’ll be in the hands of the FA.

“Usually it will take about two weeks but it might be a bit quicker because of Covid.

“First they review the incident, then the FA will ask both clubs of their observations and that will be reviewed by a panel of three with an independent chairman.

“It’s difficult to say on the punishment. There’s a range of punishments that are financial and suspension.

“You can’t put a fixed term on it. Has the person been put before them before? Does he have a record? All those sort of things come into play.”

In other news, a Sunderland chief has pocketed £700,000 from a blockbuster Birmingham City transfer.