The optics aren’t great. And sometimes it is all about juxtaposition. Kyle Walker is 27, with 198 top-flight appearances and 27 international caps. Leo Bonucci is 30, with 265 top-flight appearances and 70 international caps. Walker has won nothing in his career and has played three Champions League games. Bonucci has won six league titles, three domestic cups and was twice a Champions League finalist. He has 38 Champions League matches under his belt.

Both are defenders who fell out with their previous managers. Both signed for new clubs on Friday. Guess who cost nearly £15 million more than the other? Actually don’t, because you already know. Walker set two records on Friday when he signed for Manchester City in a reported £53m deal, making him both the most expensive defender in the history of the game and the most expensive English footballer ever – at least, that is according to a tweet by his agents, Base Soccer.

Others, perhaps briefed by the club who don’t want him saddled with the pressure of two world-record fees, put the fee at £45m, rising to £50m based on performance, which would place him a smidgeon behind the current most expensive defender, David Luiz. Either way, it’s a ton of money and 25 per cent more than what Milan paid to secure the services of Bonucci.

Some react to this by throwing their arms in the air and talking about how that’s the “going rate” in a “market” which has gone “crazy”. There’s not much you can do with those people. Once folks start to think that something is “structurally irrational”

– as opposed to, say, a club making a poor decision, you are not going to reason with them.

Others believe the move – and disparity of fees – can be explained by market forces. Bonucci is, after all, three years older and will earn some £3.5m more per season. Assume for a minute that both will play until they are 34. Spread out the fee – or, amortise it, if you are of more of an accounting bent – and Bonucci will cost Milan £19m a season, whereas Walker will cost around £13.5m a year. So Bonucci is costing some 50 per cent more, which makes sense since he is one of the top five players in the world at his position.

But there are other factors pushing up Walker’s fee. City do not have a right-back. Nor do they have too many senior pros who fulfil the Premier League’s home-grown player requirement, that is three seasons at a Welsh or English club before their 21st birthday. In fact, at the start of last year they had just four. One, Gael Clichy, is gone and another, Fabian Delph, started just two league games last season and is up for sale. Without Walker – and with Delph likely moving – they would have to go through the season with just 19 senior pros. Then there is the fact Daniel Levy seems to have acquired voodoo-like negotiating powers, particularly when it comes to selling players and making other clubs pay through the nose.

All that is fine. But then you have forces working in the opposite direction. Walker fell out of favour at Spurs at the end of last season and was entering the final two seasons of his contract. City had other options, such as Arsenal’s Hector Bellerin, who is five years younger and who also would have fulfilled the home-grown player requirement.

But maybe the most puzzling aspect of this deal is Walker himself. A week ago, before being gazumped by Paris Saint-Germain, City thought they had solved their right-back problems by picking up Dani Alves on a free transfer. Sure, he is 34, but as a short-term solution he fitted the bill. He has been a Pep Guardiola loyalist and he was outstanding in the Champions League last year. He is a gifted, creative passer and dribbler with bags of experience in Guardiola’s system. Without getting into the issue of quality, Walker is an entirely different player. He is a straight-line runner, blessed with athleticism more than technical ability. He will have to learn City’s system and appears to be anything but an obvious fit.

So maybe the explanation that applies is the simplest one. Guardiola thought he had his squad in place with Alves’ arrival, just as training camp was getting started. And, suddenly, he didn’t. So he told the club to pull the trigger because having a live body in the right-back position is obviously more important to him than saving a few quid.

That is not the transfer market going “crazy”. Nor is it “market forces” at work. It is simply an impulse buy, caused by necessity. Same reason you would pay £10 for a bottle of water if you were walking through the desert and dying of thirst, not realising there is a corner shop just over the next dune.

CHELSEA and Manchester United have been running their transfer business in parallel this summer, which may not be surprising when you consider the similarities (though there are clear differences too) between Antonio Conte and Jose Mourinho.

Both pursued Romelu Lukaku and Alvaro Morata. The former signed for United, the latter remains a Chelsea target. Both picked up a versatile, athletic defender: Victor Lindelof is at Old Trafford, while Antonio Rudiger is now at Stamford Bridge. And while Chelsea sealed the deal for a tall central midfielder yesterday (Tiemoue Bakayoko), United are reportedly one step closer to their own version of said midfielder, who happens to be the guy Bakayoko is replacing: Nemanja Matic. The big Serb was left out of Chelsea’s squad for their tour of Asia as the club expect negotiations for his transfer to pick up steam very soon.

The symmetry is evident in terms of the types of players these two managers crave, as is the fact both men grow antsy when they feel a club aren’t delivering transfer targets quickly enough. In a league increasingly dominated by managers who emphasise possession and high pressing, these two are cutting against the grain.