SILVERSTONE bosses have asked Prime Minister David Cameron to stop state aid from being used to help build a proposed £280m circuit in Wales.
The Welsh and UK governments are being asked by developers of the Circuit of Wales scheme in Ebbw Vale, Blaenau Gwent, for up to £50m.
According to the Heads of the Valleys Development Company the scheme will create 6,000 jobs and bring 750,000 visitors a year to the area.
There are plans for hotels, a grandstand, a technology park and a solar park, alongside the track.
But Silverstone managing director Richard Phillips has written to Mr Cameron over the issue.
His letter said: "An injection of funds by the Welsh and/or UK governments to the Circuit of Wales project would amount to a transfer of state resources, which gives Circuit of Wales an economic and selective advantage over other circuits. As such, it could amount to illegal state aid.
"There are a number of well established, privately funded circuits in the UK, including Wales, that feel that the British motor sport industry would be threatened by the addition of a government-funded circuit."
A body which represents 17 UK race tracks, The Association of Motor Racing Circuit Owners, has argued that the circuit would harm motorsport.
But it has been reported that the Welsh government is considering investing £30m in the project.
The circuit hopes to secure the rights to host MotoGP, which attracts global audiences of up to 300 million, from September, 2015.
But building work, which was due to start last December, has been delayed by planning issues.