A member of Southampton's staff was spotted filming one of Middlesbrough's training sessions in the run-up to the play-off semi-final between the two clubs, which Southampton ultimately won.
Shortly before it, the Football League (EFL) had already begun an investigation into the allegations and charged Southampton with spying, and they announced afterwards that there was a chance that the final wouldn't go ahead as scheduled while they continued to look into matters.
Middlesbrough then formally called for Southampton's expulsion, and in a hearing on Tuesday, they got their request granted, with the EFL expelling Southampton and handing them a four-point deduction for next season.
"An Independent Disciplinary Commission has today expelled Southampton from the Sky Bet Championship Play-Offs after the Club admitted to multiple breaches of EFL Regulations related to the unauthorised filming of other Clubs’ training," a statement from the league's governing body read.
"In addition, the Club has received a four-point deduction that will be applied to the 2026/27 Championship table."
Middlesbrough will now go up against Hull at Wembley with a place in the Premier League on the line.
"The effect of today’s order is that Middlesbrough are reinstated into the 2026 Play-Offs and will proceed to the Play-Off Final against Hull City. The final remains scheduled for Saturday 23 May, with the kick-off time to be confirmed," the statement concluded.
Boro welcomed the ruling and stated that they'd be ready to contest the final later in the week despite the short notice.
"Middlesbrough Football Club welcomes the outcome of today’s Disciplinary Commission hearing," they said.
"We believe this sends out a clear message for the future of our game regarding sporting integrity and conduct.
"As a club, we are now focused on our game against Hull City at Wembley on Saturday."
As per the EFL, Southampton admitted to multiple breaches in regard to unauthorised filming at the training grounds of Middlesbrough and other opponents ahead of matches.
However, they have reportedly already appealed the final verdict, and the EFL haven't ruled out the play-off final being postponed.