The rumours linking Toby Alderweireld to Manchester United are becoming more frequent by the week.

Last night delivered the arguably most promising of all for United fans. According to the Mirror, the Red Devils have already entered talks for the Tottenham centre-back but Spurs could demand a fee in the region of £75 million.

The idea is that the north London club will try and match the fee received by Southampton when they sold Virgil van Dijk to Liverpool in January.

You can't exactly fault Spurs for demanding such a hefty fee, too.

Alderweireld has been a stalwart for the club across his three seasons in the white jersey and earned himself a place in the PFA Team of the Year for his performances in 2015-16.

Man Utd want Alderweireld

He was also named the Tottenham Player of the Year that season and wiggled his way into the Europa League Team of the Year.

This season has been one of frustration for the Belgian, making just 14 Premier League appearances due to injury, but it hasn't damaged his reputation as one of the competition's finest defenders.

And with his contract due to expire in 2019, the pressure is on for Tottenham to either negotiate a new deal or secure a summer sale to ensure they're duly compensated.

Interesting clause in Alderweireld's contract

Enter Manchester United.

While there's every reason to suggest the Red Devils would meet the £75 million asking price, there's an interesting clause in Alderweireld's Tottenham contract that could provide a far better alternative.

The Times reported in February: "Alderweireld’s situation is complicated by the nature of his contract, which is due to expire in 2019 but has a clause that enables the club to extend it by 12 months.

"However, the same clause also allows Alderweireld to leave next summer for £25.4 million before the final 14 days of the transfer window, so the end of this season represents Spurs’ last chance to achieve his full market value, which would be more than £50 million."

As a result, Spurs have until Deadline Day this summer to ensure they receive the full market value for the 29-year-old. Otherwise, United could have him for free or £25.4 million at most.

This clause is applicable until the final 14 days of the 2019 summer transfer window.

United shouldn't be too disheartened if the £75 million asking prices proves a difficulty because they should have a free shot if Alderweireld starts next season at Tottenham.

The whole situation has forced Tottenham to look to sell this summer to try and procure a larger fee.

Whether Spurs trigger or ignore the contract extension, United look to have the situation in complete and utter control.

They will no doubt face competition for his signature but Tottenham look well and truly cornered on the matter.

A price tag of £25.4 million would look an absolute steal for United if they're able to back Tottenham into triggering a one-year extension that simply buys them time.

Do you think Alderweireld would be a good signing for United? Have your say in the comments section below.