Barcelona confirmed that they were notified by Lionel Messi of his decision via burofax, a service used in Spain to urgently dispatch a document that requires proof to third parties.

The club responded to Messi via the same service saying they want him to stay and finish his career at the club.

Messi has a contract until 2021, but he believes he has a clause in his contract that should allow him to leave for free. Barcelona maintains that the particular clause expired at the start of the summer.

The clause stipulated he could leave for nothing at the end of each season as long as he communicated his decision to Barca before June. Messi's legal team are arguing the extension of the season altered the expiry date of the clause.