But football's world governing body has issued a warning to Real of the consequences of inducing the Portugal winger to breach his contract.

FIFA said in a statement that they had received a complaint from United last week but that no regulations had been broken by the Spanish club so far.

FIFA's statement read: "We can confirm that we received last week a formal complaint from Manchester United related to the player Cristiano Ronaldo and the club Real Madrid. From the documentation received, no breach of contract appears to have occurred yet.

"Therefore, in accordance with the applicable practice, no kind of formal procedure has been opened by FIFA regarding this matter.

"The Spanish Football Federation has been informed of the complaint lodged by the English club and been asked to remind its member club Real Madrid about the potential legal consequences of a breach of contract without just cause during the protected period and of a possible inducement to such a breach of contract, as established by the FIFA Regulations on the Status and Transfer of Players."