Last month, broadcaster SER Catalunya alleged Barca had paid €1.4million to the company of Jose Maria Enriquez Negreira – the former vice-president of Spain's Technical Committee of Referees (CTA) – between 2016 and 2018.

Newspaper El Pais claimed Negreira's company – DASNIL 95 SL – produced written reports and DVD assessments of referees prior to games.

The public prosecutor's office said on Friday that Spanish prosecutors had filed a complaint against Barca and two of their ex-presidents, Josep Maria Bartomeu and Sandro Rosell, over the alleged payments. It has been claimed the total payments exceeded €7m, dating back to 2001.

The saga may end up being resolved in court, although that is not certain at this stage. Madrid's board met on Monday (AEDT) and expressed its "utmost concern regarding the gravity of the facts".

A Real Madrid statement read: "In their meeting held today, the Real Madrid CF board of directors have inspected the serious accusations brought by the Barcelona prosecution service against FC Barcelona, two of its former presidents, Josep Maria Bartomeu and Sandro Rosell, and executives Albert Soler and Oscar Grau, on the basis of alleged offences of corruption in sports, among others, all related to the relationship the club maintained with the former vice-president of the CTA, Jose Maria Enriquez Negreira.

"Real Madrid wishes to express its utmost concern regarding the gravity of the facts and reiterates its confidence in the legal system. The club has agreed that, in defence of its legitimate rights, it will appear at the trial when the judge opens it up to the affected parties."

Barcelona's current president Joan Laporta used Twitter on Monday to attempt to reassure fans, writing: "Culers [Barca fans], you can be calm. Barca is innocent of the accusations made against it and is the victim of a campaign, that now involves everyone, to harm its honourability.

"It is no surprise, and we will defend Barca and prove that the club is innocent. Many will be forced to rectify."