While Barcelona have put a deal for Williams in place, the club remain under strict financial constraints.

The ‘1:1 rule’ states that the club can only spend as much as their income and accounts allow, with La Liga calculating a limit based on the club’s expected income.

Club president Joan Laporta says the club will comply with that rule but it is not clear yet how they will be able to finance their summer arrivals, as renovations to the Nou Camp has increased club debt, and income is still insufficient.

Barcelona signed Espanyol goalkeeper Joan Garcia earlier this week in a 25m euros (£21.3m) deal and La Liga president Javier Tebas has warned that the club will not be able to register new players unless they prove they are compliant with their financial rules.

“One thing is to make the signing of Joan Garcia official and another is to register him,” said Tebas.

“Barca has to do things to be able to register him, not many, but they have to do things and they already know what they are, I’m not going to say them.”

La Liga revoked Barcelona’s registration of midfielder Dani Olmo in January, having given the club permission to temporarily register him following his arrival from RB Leipzig.

The league claimed Barcelona had failed to prove they were complying with financial rules by a deadline of 31 December.

Spain’s National Sports Council (CSD) later overruled the decision, allowing Barcelona to reinstate Olmo.