The Daily Mail says the move will be completed next week, subject to any challenge from West Ham, who still claim to own the registration of the player who saved them from relegation last season.

However, West Ham have no contract with Tevez and his owner, businessman Kia Joorabchian, which has left the player and his representative free to negotiate a transfer with other clubs.

The news, breaking in South America last night, means that United will take their summer buying past the £70m mark, confirming them as the biggest spenders in world football.

Tevez was once fined when playing for Brazil's Corinthians for turning up to an official press conference wearing a Manchester United shirt.

He will fly from Argentina's Copa America base here to join United's pre-season programme.

"He just cannot contain his excitement at the news," a source close to the Argentina camp confirmed. "Tevez has been concerned about his future, worried about where he may play next season and now he is joining the biggest club in the world! This is massive news."

Tevez is best friends with United's Argentine defender Gabriel Heinze and was a guest at their end-of-season title party in a London club.