Spanish football faces a potentially huge match-fixing scandal after an unnamed linesman alleged that he had been told to favour Real Madrid in next month’s clásico against Barcelona.

The linesman said that he did not want to be identified because of concerns over “possible reprisals” but he made a formal complaint through a lawyer to the anti-corruption investigating magistrate in Barcelona in which he claimed to have been told to favour Madrid – first by another official and then, over the phone, by a member of the Spanish Football Federation’s referees’ committee.

The linesman alleged that he was told that officials had already acted to influence the outcome of games and that another linesman has been subjected to similar pressures. According to his lawyer, Jacinto Vicente Hernández, an expert in sports law based in Barcelona, the linesman wanted to go public with the allegations but he persuaded his client to make a formal, legal statement to the anti-corruption investigating magistrate instead. The Guardia Civil has also been informed.

The story was broken by the Catalan newspaper L'Esportiu on Wednesday and followed up by Cadena Cope radio station. It has made a huge impact in Spain, even if there are doubts that anything will come of it. The "denuncia" or formal complaint made by the linesman through his lawyer, dated October 19th, has been published. In it, the linesman recognises that a telephone conversation he says took place was not recorded and that there is no concrete proof, but expresses the hope that the other linesman will also come forward.

José Ángel Jiménez Muñoz, who is reported as being the member of the referee's committee accused of having made the telephone call to the linesman in question to apply extra pressure, said late on Wednesday night that he had not yet had the chance to read the "denuncia" but said of the allegations: "I have no idea where they come from. It is like something out of a Kafka novel." Barcelona's vice-president Susana Monje said: "I hope it does not prove to be true."

Later, she added: “We will possibly discuss at it a meeting of the board. All I can say at the moment is that if it is confirmed, it will be dangerous story in terms of the prestige of La Liga.” The claims have not been substantiated.

Miguel Cardenal, the Spanish secretary of state for sport, said: "This is an extremely serious accusation and is extraordinarily alarming. This needs to be resolved as soon as possible. We cannot be talking about threats without knowing who is it. No one should be scared. It cannot be reasonable that in 2015 someone can fear reprisals for making an accusation like this."

The linesman, who forms part of one of the officiating teams that could be designated for the clásico, alleges that an official spoke to him in September and suggested that, should they be given the chance to officiate the clásico, he should seek to influence the game in Madrid’s favour. The linesman was allegedly told that the order had come from “someone inside [the refereeing authorities]” and that it was better for the linesman to try to fix the game than a referee as the lead official is subject to greater media scrutiny.

He claims to have been told that this had already happened this season and that, as it caused a stir, it was better to be more “subtle”. The linesman says that he was not comfortable with the suggestion and that the official replied that nor was he but that as they are constantly rated by the referees’ committee, and their careers depend upon that committee, it would be wise to follow orders.

The linesman alleges that a few days later he received the phone call from Jiménez Muñoz, who had been made aware of his reluctance to participate. His lawyer suggested that he call back and record the conversation but the linesman said that as the alleged call had come through the switchboard, that was impossible.

According to his lawyer, he wanted to speak out in order to relieve the pressure that he felt he was being put under. He also said that he hoped that the other linesman, whom he did not name, would step forward.

Having made the formal statement to the authorities, the next step would be the opening of an investigation, should it be considered that there is sufficient grounds to do so. But the linesman admits that there is no hard evidence.

Real Madrid have yet to comment.

(Guardian service)