Madrid, Oct 23 (IANS): Spanish football faces perhaps its biggest scandal yet after a linesman made allegations he had been told to favour Real Madrid in the 'El clasico' against FC Barcelona at home next month.

The official, who has remained anonymous "because of possible reprisals" has made a formal complaint to an anti-corruption magistrate alleging that during September he had been told to favour Madrid by another official, reports Xinhua.

A member of the Spanish Football Federations' refereeing committee and the Spanish Civil Guard are now investigating the case.

It is debatable how far the investigation will reach given that the linesman did not record the conversations in which he alleges he was told to favour Real and Jose Angel Jimenez Munoz, the referee committee member accused of making the call, says the allegations are "like something from a Kafka novel".

Barcelona vice-president Sonja Monje expressed her hope that the allegations "do not prove to be true," adding the story was "dangerous in terms of the prestige of La Liga".

Meanwhile, Spain's Secretary of State for Sport, Miguel Cardenal is taking the matter seriously, saying, "This is an extremely serious accusation and is extraordinarily alarming. This needs to be resolved as soon as possible."

He appealed for the linesman, who is said to work with one of Spain's top referees to reveal his identity.

"We cannot be talking about threats without knowing who it is. No one should be scared. It cannot be reasonable that in 2015 someone can fear reprisals for making an accusation like this," commented Cardenal.

Spanish football league (LFP) president Javier Tebas was less open to suggestions of match fixing in what is effectively the biggest club game in the world.

"This allegation seems a bit far-fetched. It makes no sense, when the referee for this game has not been designated," he said.

However, Tebas overlooks the fact that for such a big game there is a very limited group of referees considered experienced enough to officiate in the match, with only three or four candidates likely to be considered.

Those referees are now under huge pressure and as the pro-Barcelona newspaper, Diario Sport headlined on Friday, the 'Clasico' is now the game "nobody wants to referee."

Real, who have not been directly implicated in the accusations, have so far made no official comment.