The Blades' lawyers say they have instituted "arbitration proceedings" against the Premier League, and want a three-man tribunal set up to rule on the dispute.

The Premier League have confirmed receipt of the claim but it is understood they are not obliged to agree to enter into the process. "We are considering the request," said a spokesman.

An independent commission fined West Ham 5.5 million pounds (10.8 million dollars) for breaching Premier League rules over the signing of Tevez and Javier Mascherano last year, but several clubs felt they were let off lightly.

Argentine striker Tevez played a key role in West Ham's escaping the drop as he scored seven goals in the club's last 10 games, while Sheffield United were relegated.

And the Blades' lawyers are challenging the legality of the independent commission's decision.

A statement from Sheffield United read: "We are challenging the legality of the League commission's decision to hand West Ham a fine rather than (as had been universally expected) docking West Ham points and cancelling the registration of Mr Tevez."