That’s led to his club’s co-owners, chairman Simon Blitz and managing director Simon Corney, threatening to quit football if the deal goes through.

Whatever the rulebook says, they believe they are morally entitled to compensation for the 23-year-old, who scored 23 goals in 37 starts last season and has been tracked by a string of big clubs.

From the Tangerines’ point of view, though, over the weekend chairman Eddie Thompson has confirmed an interest and he is satisfied they are working within the rules.

It’s understood Porter will give his answer in the next day or so and, in advance of that, Tannadice boss Craig Levein has declined to comment.

If the player decides to move, it will be in identical circumstances to those that saw Andy Webster quit Hearts for Wigan last year.

And Porter would have to be mindful that, should he fail to settle and want to head back to England within a year, he would be obliged to pay the equivalent of a transfer fee to Oldham — reports of his valuation vary between £700,000 and £1 million.

United, meanwhile, have made it clear they expect another striker — Thierry Henry — to be making an appearance at Tannadice next month.

The French superstar was at the Nou Camp today undergoing a medical before completing his £16 million move from Arsenal, but reports this morning stated his debut for the Catalans would be against Hearts at Murrayfield — two days after the July 26 friendly in Dundee.

That was news to United, who have a contract with match organisers Platinum One which states all fit and available first-team players must be involved.

The only exceptions to that are Argentine striker Lionel Messi, who will still be on holiday because of his involvement in the Copa America, and Barca captain Carles Puyol, who is out injured for three months.