Harry Maguire has played in a World Cup semifinal and become one of the most highly rated defenders in the Premier League, but even his most ardent supporters would struggle to argue that he is the very best at his position.

Yet if Leicester get their way and force Manchester United to pay in excess of £80 million, the 26-year-old will become the most expensive defender in the world. That would eclipse the £75m that Liverpool paid for Virgil van Dijk -- not only the world's best defender but the favourite to win the Ballon d'Or this year.

All this for a player Leicester signed from relegated Hull City for an initial £12m just two years ago.

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Sources have told ESPN FC that, while United manager Ole Gunnar Solskjaer is determined to sign Maguire as quickly as possible to reinforce his porous defence at Old Trafford, the two clubs are still some distance apart in terms of their valuation.

United, who initially offered £40m for Maguire last month, are now prepared to pay closer to £70m to get their man, but Leicester's starting point is £80m and some reports suggest they are even ready to hold out for £90m.

Yet for all of Maguire's ability as a commanding centre-back, a player with an aerial threat in both boxes and one who can play the long and short game, it would signal a new, eye-watering benchmark in an already over-heated transfer market.

Leicester are smart operators when it comes to selling players. They banked £60m when selling Riyad Mahrez to Manchester City 12 months ago and also forced Chelsea to hand over £35m for midfielder Danny Drinkwater in 2017. The Foxes hierarchy know that United, having seemingly missed out on Ajax captain Matthijs de Ligt, are short on alternative options for a proven, commanding defender, so they are quite rightly putting the squeeze on the club's executive vice-chairman Ed Woodward.

Woodward, an investment banker with JP Morgan prior to working for United, knows all about market forces and it is unfortunate for him and his club that they are now on the wrong end of the spike in transfer fees. But City were also forced to pay over the odds when they paid £50m to sign Kyle Walker from Tottenham two years ago, making him the world's most expensive full-back at the time, while Liverpool's wisdom was questioned when they paid £75m for Southampton's Van Dijk 18 months ago.

City and Liverpool would now both argue that they were justified in breaking transfer records to sign Walker and Van Dijk, and United must now decide whether Maguire is likely to prove as smart a long-term investment as those two, even if the costs seem alarmingly high.

United's history, certainly since Sir Alex Ferguson's time in charge, is littered with examples of expensive signings which ultimately proved to be sound investments.

Gary Pallister (£2.3m), Roy Keane (£3.75m), Ruud van Nistelrooy (£19m) and Rio Ferdinand (£30m) all became British record signings when they moved to United, while Wayne Rooney was the world's most expensive teenager when he completed a £27m move from Everton in 2004.

All of the above left Old Trafford having more than justified their huge transfer fees, with each of them proving that the initial outlay was excellent value in the long term.

However, United's sense of value has deserted them since Ferguson retired in 2013, with those in charge too often knowing the price of something rather than the value.

Which is why they are now in a difficult position with Maguire. Is it another case of having to pay vastly over the odds for a player who will never live up to the pricetag? Or is Maguire a modern-day version of Pallister or Ferdinand, two defenders whose fees were questioned at the time, but who ultimately made the cost of the transfers look cheap?

One thing for certain is that Maguire is not the best defender in the world. True, Van Dijk wasn't either when he traded Southampton for Liverpool, but the Dutchman now has few rivals for that title after a sensational 18 months at Anfield. His £75m fee now looks to be a bargain and Liverpool could double it right now if they were foolish enough to consider selling.

It would be naive for United to expect Maguire to follow the same path so quickly. But he is better than what they have and would improve United, so the price is the price and they have to accept that market forces have left them having to break the world-record transfer fee for a defender.