West Ham United were last night facing a multimillion-pound lawsuit in the battle over the future of Carlos Tévez after the player’s agents issued a writ against the club. Legal proceedings began after Fifa refused to rule on the player’s potential transfer to Manchester United, referring the case to the Court of Arbitration for Sport (CAS) in Lausanne.

Kia Joorabchian, who fronts the two companies that hold Tévez’s “economic rights”, Media Sports Investments (MSI) and Just Sports Inc (JSI), turned up the pressure on West Ham after the club, who hold Tévez’s registration, declined to sanction a move to Old Trafford that could be worth more than £20 million to the Argentina forward’s agents.

Graham Shear, who is representing the companies, said that they would also be seeking damages from West Ham. “The companies seek the court’s intervention to compel West Ham to release the registration of Carlos Tévez in accordance with contracts entered into between the parties,” Shear said. “We are asking the court to intervene so Carlos Tévez can be registered to play with Manchester United as soon as possible.”

Joorabchian claims that West Ham unilaterally ripped up the contract that was agreed last summer when Tévez and Javier Mascherano, his Argentina teammate, arrived at Upton Park. Those deals were deemed to be in breach of Premier League rules by a commission that fined West Ham £5.5 million in April.

As part of the punishment, the club were forced to extricate themselves from the contract with MSI and JSI, a move that allowed Tévez to play in the final three games of the season, helping them to avoid relegation.

Richard Scudamore, the Premier League’s chief executive, said that West Ham would have to abide by the decision the club made in April, which allowed them to play Tévez. “They were given three options,” Scudamore said. “The one they chose has made it difficult for them, but we will see that that choice is upheld. They could have gone a different way.”

Had West Ham chosen to maintain the contract with Tévez’s agents, the forward would not have been allowed to play for the club again. MSI and JSI argue that they did not agree to the contract being terminated. West Ham claim that they are only one year into a four-year deal with the striker. Last night, the club were consulting their lawyers.

The Premier League refused to ratify a transfer to United unless the bulk of any fee was paid to West Ham. The League hoped that Fifa would mediate to resolve the situation, but football’s world governing body backed away from making a ruling that it feared could be challenged in a court of law. “It is not a matter of refusing to arbitrate but a recommendation in the interest of all parties involved in the complicated affair,” a Fifa spokesman said. The CAS could intervene only with the agreement of both parties, but only West Ham said that they would be willing for the court in Swit-zerland to consider the case.

MSI and JSI may not be keen to use the court because they may have no further legal recourse if a decision goes against them and because proceedings would take place behind closed doors. The companies also argue that the CAS could take too long to reach a verdict, although the court said yesterday that it would find a resolution before the end of the transfer window next month.

The CAS was set up to provide a forum for settling sports disputes quickly and fairly. The Football Association is also willing to begin an arbitration process to end the dispute, but no party has yet asked it to.