Mbappe vs PSG is the toxic feud with the relationship beyond repair

France's captain and its biggest club are at war. With no sign of a ceasefire in sight the battle between Kylian Mbappe and Paris Saint-Germain rages on.

Here, Mail Sport's MIKE KEEGAN examines an explosive feud that has split the country and captured headlines across the world.

He finds allegations of betrayal, naivety, staggering amounts of cash and a relationship that appears to be beyond rapprochement.

For Paris Saint-Germain it is simple. In May 2022, Kylian Mbappe agreed a contract extension to remain with his hometown club until 2025. He went onto the pitch at the Parc des Princes with president Nasser Al-Khelaifi and the grinning pair held aloft a shirt with 'Mbappe 2025' on the back.

The crowd, on a Spring evening of celebration in the French capital after another Ligue 1 title, roared its approval. Metz would be thrashed 5-0, with Mbappe scoring a hat-trick. All was well, and then all went to hell.

Less than two months after that happy day, Mbappe wrote a bombshell letter which the club did not receive until June of this year. In it, the 24-year-old bluntly informed his fellow shirt-holder he would not be taking up the offer of an additional 12 months on his new two-year deal and would, in fact, be leaving at the end of 2024.

Effectively, a £250million asset in which they had invested more than half a billion euros, after a £166m move which saw him initially join on loan from Monaco in 2017, would stroll out of the door for free. 'Please accept, Mr President, the expression of my respectful sentiments,' the letter starkly concluded.

For PSG, this is the case of a greedy footballer who has gone back on his word. A player they are convinced has a secret agreement with Real Madrid in place, to cross the Pyrenees at the end of the season for an incredible signing-on bonus of £137m.

The figure is so high because there will be no transfer fee for the best player on the planet. PSG get stiffed and, as a direct result, Mbappe gets even wealthier.

For the man at the epicentre of the earthquake, it is also simple. He agreed, in writing, a deal to 2024 with the option of a further 12 months. At no point, in writing, did he commit to honouring that extra year.

Mbappe is a born winner. He wants to win the Champions League. He does not feel he can do that at PSG and has been underwhelmed by the Qatar-owned club's recruitment.

As a result, he will be seeking pastures new in 12 months' time, as is his right. In December, Mbappe was scoring a hat-trick for his ultimately defeated country in a World Cup final for the ages. In August, he is training with his club's B Team and signing autographs for a dozen diehard bystanders after being barred from PSG's tour of Japan, of which he was meant to be front and centre.

All marketing featuring Mbappe was rapidly dropped when the row escalated. When the club unveiled their new kit this week, their star man was nowhere near it.

PSG are wounded. They feel they have every reason to feel that way. Mail Sport has learned that Mbappe is paid around 75m euros net a year. His signing bonus was 110m, along with a loyalty bonus of 60m. The prospect of Mbappe leaving on a free after all that investment has left them incensed.

In the club's most recent correspondence with the player, seen by Mail Sport, they accuse the player of inflicting on PSG 'a lasting paralysis'. They say years of 'unprecedented goodwill, commitment and investment' should lead him to 'think about the future of the club and the great fans who have supported you all this time'.

Their solution is simple: go now, and let your club pick up a fee for you. The signing of Mbappe's potential replacement, Ousmane Dembele of Barcelona, has only served to further frustrate PSG. There was no playing up at the Nou Camp from a player who wants to do best by his current employer and who can also leave for nothing in 12 months.

Officials are also wary of the Harry Kane situation, where the Tottenham striker has not agitated to speed up a switch to Bayern Munich and lower the fee in the process, given he is in a similar position with his contract.

There is also anger at Mbappe's entourage. It is understood that, ahead of their final home match of last season against Clermont, a close connection was heard loudly complaining about the quality of the side in front of guests in the VIP area. 'Real Madrid have got (Jude) Bellingham,' they are alleged to have stated, 'and Paris have got Marco Asensio', in a clear damning indictment of the French club's likely summer business.

To speak that way of Asensio, a three-time Champions League winner, was viewed as deeply distasteful.

There have also been claims from within the B Team training camp that Mbappe has been telling them they are more talented than the squad currently in Japan - which happens to include his 16-year-old brother - while smiling and signing autographs for the fans outside in the public gaze.

Mbappe's unhappiness with transfer activity has also hit a nerve. PSG are often accused of signing marketing opportunities rather than players in areas of need and, with the likes of Neymar and Lionel Messi onboard together last season, ending up with an unbalanced squad.

The view inside the club, however, is that if Mbappe reduced his wage demands it would free up cash to invest elsewhere.

There have been other issues which some believe prove the player caters only for himself.

In April, Mbappe took to social media, lambasting the club for using him in a video to promote season ticket sales, claiming they had not told him how they intended to use the interview. While a young member of the marketing team was subsequently hauled over the coals, there was a view Mbappe could have made a private call to the club for an explanation and avoided such an episode.

When it comes to use of media, they point to eight occasions on which they believe Mbappe has made it clear in interviews he would never leave on a free.

Then came his comments in June, when asked if people now 'trivialise' his performances. His response was that playing for PSG 'does not help'. He then said his club had reached 'a glass ceiling' and that those 'who build the team' should answer questions.

As for the letter itself, there is confusion over why he would wait close to a year to send it.

Because this is elite football in 2023, money is at the centre of everything. UEFA's Financial Fair Play rules swirl around the row.

There is a fear at PSG that if Mbappe goes, the giant hole he leaves may trigger redundancies. If such an asset is stripped from the balance sheet, adjustments will have to be made.

Above all else, the player has the power. Late last month, a £259m offer came in from Al-Hilal of Saudi Arabia. It would have yanked Mbappe's club out of a hole but he turned it down without entering into discussions.

It is a long list of accusations but, as with most stories, there are two sides.

Mbappe holds the aces. Despite holding the 2025 shirt aloft, he did not sign anything committing himself for that time period. He says PSG have known of his intentions after he verbally outlined them more than a year ago. In his world, he is honouring his contract and acting in accordance with it.

Those who know him say these are the actions of a born winner, rather than someone who wants to have more money than God.

There is a view that PSG made promises to build a team to win the Champions League and that they are no closer to that two years after the contract was signed. Last season they were knocked out in the last 16 by Bayern Munich.

If anything, they argue, Mbappe is the one who has a right to feel betrayed. They point to this summer's transfer business so far and claim PSG's central midfield remains a million miles from Europe's best.

Mbappe has long held a desire to go to Real Madrid but signed an extension to his deal, having been told that players who would help him win the trophies he craves were on their way. The view is that this has simply not happened.

Meanwhile, the clock is ticking. Mbappe will be 25 in December.

So what next? PSG start the Ligue 1 season on August 12 against Lorient. It is unlikely Mbappe will be in the starting XI or even on the bench.

The club are desperate to minimise their loss. An escape route to the Premier League for 12 months, with Chelsea and Manchester United among those to have expressed an interest, is deemed unlikely.

Those close to the trenches believe that the prospect of a year in the wilderness ahead of the Paris Olympics - at which Mbappe may play a starring role - is unfathomable.

Real Madrid may come to the player and club's rescue with a late bid, but even then there would be a long way to go before a deal is done. PSG would want around £130m, which would have a huge impact on the suspected giant signing-on fee.

Compromise has to be reached before a solution can be found. It seems distant. For now, PSG are considering reporting Madrid to FIFA for what they believe is an illegal approach.

France itself is torn as the new season approaches. Those with knowledge of PSG's fans and their raucous ultras say the situation is complex. Although they may welcome Mbappe's marginalisation if he stays, another early Champions League exit would trigger a clamour for his return.

A move out on loan would, at least, lessen the financial impact and restore some semblance of control to PSG.

The market remains open until September 1. All of France - and Spain and England - is watching.