Middlesbrough are preparing to sue the English Football League alleging it failed to enforce financial rules surrounding Derby County’s purchase of their own stadium, allowing the Rams to avoid breaching 'Financial Fair Play' regulations and a potential points penalty.
Derby finished a point ahead of Middlesbrough last season, denying them a place in the Sky Bet Championship play-offs and the lucrative prize of promotion to the Premier League.
According to reports from the PA news agency, the Teesside club are planning to sue the governing body over what they will argue is a loophole.
In May, Derby owner Mel Morris used another of his companies to buy the club's stadium, for £80 million, reported to be almost twice the £41million value listed on the club's books, and then lease it back to the Rams.
Derby were able to post a pre-tax profit of £14.6million and avoid sanction under EFL profit and sustainability rules which prevent clubs from making losses of more than £13million a year over a 36-month period.
Middlesbrough were not commentating on a report on Friday which claimed they are to sue the league over the matter, although according to PA sources on Teesside confirmed legal advice has been taken.
An EFL spokesman said: "We do not comment on the financial circumstances of specific clubs."
Mel Morris is insisted his club had committed no offences, telling talkSPORT: "We've done nothing wrong. We're very comfortable with what we've done. The valuation, in our opinion, was fair and reasonable.
"We didn't use a loophole. Let's be very clear on this, there is no loophole here. The rules are extremely specific on this, that the sale of a fixed asset is allowable. It's a single sentence. It is allowable."
Middlesbrough chairman Steve Gibson has been an outspoken critic of clubs he alleges have spent beyond their means without facing sanctions, as Birmingham were last season when they were docked nine points after recording a loss of almost £10million in excess of the limit.
Speaking as new head coach Jonathan Woodgate was unveiled in June, he said: "If the rule is not going to be followed, don't have it, and if the rule is there...
"If we have a centre-half who picks the ball up in the penalty area, I don't expect the referee to ignore it. If a player deceives the referee, I don't expect that to be ignored, and I don't expect the EFL and other clubs to ignore Financial Fair Play.
"It's there, it's a rule, it's an important rule, it needs to be followed and if it's not followed, sanctions must be taken against those clubs that cheat."
Asked what the solution was, Gibson replied: "That lies with the EFL. We're just Middlesbrough, we're a minnow in this. The EFL and the other clubs have got to act against it."