Exclusive by Phil McNulty
Chief football writer
Arsenal have warned Manchester United that Patrick Vieira is not for sale after Sir Alex Ferguson was linked with a £22m bid for the Highbury captain.
It was reported that Ferguson had ordered the Manchester United hierarchy to investigate the possibility of bringing Vieira to Old Trafford.
Vieira has only one year left on his Arsenal contract and negotiations are ongoing over a new contract to keep him at Highbury.
But Arsenal vice-chairman David Dein told BBC Sport that Vieira was not for sale at any price.
Ferguson is a massive admirer of Vieira and an attempt to take Arsenal's captain away from his arch-rival Arsene Wenger would represent the biggest transfer coup of his career.
United attempted to sign Vieira two years ago, but the deal never got off the ground.
And Arsenal vice-chairman Dein was defiant as he told this website: "Patrick Vieira is not for sale.
"We have not had any inquiry from Manchester United for Patrick and even in the event of one he is not for sale."
Arsenal have fought off interest from Real Madrid in the past, and Wenger is determined to keep him at Highbury after his France colleague Thierry Henry signed a new three-year contract at the club.
And 27-year-old Vieira stated on a recent visit to Senegal that he could never see himself playing for Manchester United.
On Tuesday, Vieira announced he would be fit for the start of the new season after missing the title run-in with a knee injury.