Former Barcelona president Joan Gaspart insisted Lionel Messi cannot leave the embattled LaLiga giants on a free transfer as he hit out at the six-time Ballon d'Or winner.

Messi has sensationally told Barca he wants to leave the club, who replaced Quique Setien with Ronald Koeman after they were dethroned by Real Madrid in LaLiga and humiliated by Bayern Munich in the Champions League quarter-finals.

The 33-year-old's contract runs until June 2021 and is said to have a clause in his deal that allowed him to leave on a free transfer at the end of the 2019-20 campaign.

It was required to be activated before the end of May but, due to the season being extended into August amid the coronavirus pandemic, Messi has told the Catalan giants he still intends to make use of it.

However, Gaspart – who was president of Barca between 2000 and 2003 – told Marca: "[Messi] cannot leave. He will have to leave in 2021.

"I have seen the contract and it is very clear. The clause ended in June and there is no going back.

"I prefer him to leave next year for zero than to go now for less than €700m ($827m).

"The club is in charge here, not the player. The club paid the players. And this is not a matter of money, there is a signed contract and that's it."

Having spent his entire professional career with Barca, Messi has been linked with a return to Argentina to play for boyhood club Newell's Old Boys in his hometown of Rosario.

A reunion with former Barca boss Pep Guardiola at Manchester City has also been mooted, while Inter have been long-term admirers. According to TyC Sports, a move to MLS could also be on the cards.

Messi is Barca's all-time leading scorer with 634 goals and 276 assists in 731 appearances in all competitions for the club.

The Argentina international made his first-team debut as a 17-year-old in 2004 and has won 34 trophies at Camp Nou.

"I love Messi very much, but I love Barcelona more," Gaspart said. "Let the clause be paid. They did it to me one night treacherously with [Luis] Figo and I did the same with Rivaldo, because I loved Barcelona.

"And here it's the same. There is a clause of €700m and the contracts are signed to fulfil them. I understand there is pressure from others for him to leave, but if I were the president of Barcelona then I wouldn't negotiate a euro.

"If Messi leaves for less than what his clause is worth it will be more humiliating than the 8-2 [defeat]. And Messi should not forget that the fans love Barcelona more than the player. And if Messi leaves next year, well, bad luck, he goes aged 34."

Gaspart added: "I don't understand why he is leaving Barcelona. Well, I do understand because I know these plays by football players well.

"We all want him to stay at Barcelona. Doesn't he want to stay? What's going on? Are the millions of club members who ask him to stay not worth it? Does he think that Barcelona have not helped him to be what he is?

"Messi is loved a lot and I hope he will enjoy one more year [at Barcelona]. I'd rather him go for free next year than this one for €699m. They shouldn't lower [his price] €1."