Diego Costa transfer agreed from Chelsea to Atletico Madrid for £57m

Chelsea have repeatedly fined Costa during his absence, insisting that he is an employee in breach of contract. The Professional Footballers’ Association blocks players being fined more than two weeks' wages but that is only in the case of them making themselves available to play. Costa has not done that and given he earns £150,000-a-week then he may well be £1.5m out of pocket.

To do this Chelsea have adhered to a four-point plan – that Costa, despite his desire to go, needed to return to England, train, get fit and get himself in contention – despite, also, manager Antonio Conte having texted the 28-year-old to tell him he was not part of his plans.

Chelsea were always prepared to sell Costa but the message from owner Roman Abramovich was clear: he would not be allowed to force his way out on the cheap. It almost became a point of principle at the club. Atlético, whose coach Diego Simeone has driven the deal, had initially offered as little as £26m for Chelsea’s top-scorer last season in the belief that the Stamford Bridge hierarchy would simply want rid of him. There was a fear at Chelsea that Atlético may make a similarly low offer in January.

Costa is not allowed to play until then because of the transfer ban on Atlético which may, actually, have helped him to secure his move given the club were close to signing Alexandre Lacazette before he agreed a deal to join Arsenal. Costa has been determined to return to his former club, three years after left in July 2014 when his £32m release clause was triggered, since summer 2016. Indeed he told Conte on the preseason tour of the United States 14 months ago, soon after the Italian was appointed, that he wanted  to go back to Madrid. But, at that time, Atlético bought the French striker Kevin Gameiro instead.

Costa has always been a firm favourite of Simeone who wanted him back at the club and even demanded it as part of his recent contract negotiations. The Spanish international will be allowed to train with Atlético but he cannot be registered to play for them until the ban is lifted on January 1 2018.

Fifa allows clubs to sign a contract with a player outside the transfer window and there will be relief at Chelsea that the saga is over and also that the club will not have been seen to have caved in to Costa’s behaviour.

The price agreed is a record for Atlético and Costa’s contract is expected to run to 2021. Chelsea sources estimate that the fee is comparable to the initial amount before add-ons they are paying for Costa’s replacement, Alvaro Morata, who is also, of course, vying with him for a place in Spain’s World Cup team. Costa feared that if he did not move he would be left out of the squad.

Conte has confirmed that he first decided last January that Costa could go after the forward tried to force his way out – for the second time – and pushed for a move to China with the pair involved in a training-ground row. Back then his agent, Jorge Mendes, smoothed the situation over but Conte did not forget the disruption Costa caused.

That was followed by a text message sent in June, which reiterated that Costa was not part of Conte’s plans for this season. There was concern that this had weakened Chelsea’s hand with Costa’s lawyer, Ricardo Cardoso, threatening legal action over the handling of the player who himself claimed he was being treated “like a criminal”.

Chelsea insist they have done everything by the rules ever since Costa did not turn up for pre-season training on July 10 and remained in his hometown of Lagarto, declaring the only club he wanted to play for was Atlético.

Despite his pantomime-villain image Costa was a popular figure at Chelsea and also a hugely effective striker for the club, winning two Premier League titles and scoring 59 goals in 120 appearances. However he never settled in England and yearned to return to Spain and Atlético, the club he did not want to leave in the first place.

• Who called Diego Costa a "balloon" last week?