OXFORDSHIRE racing-car design firm Wirth Research was staying tight-lipped tonight following reports of an agreement on a sponsorship deal with Virgin Group boss Sir Richard Branson.

The Bicester company has doubled in size since the announcement earlier this year that it is to build a car for Manor GP, a new team entering Formula 1 racing for the first time next year.

Spokesman Simon Crompton said he could not comment on the report in the Yorkshire Post that the Kidlington millionaire’s Virgin logo could appear on the car.

He said: “At this stage, we’re not able to make any announcements regarding who the Manor sponsors will be.”

Virgin is dropping its current sponsorship of the championship-leading Brawn F1 team, based in Brackley. However, Sir Richard has said that he would be looking to support a smaller team in the future.

Manor, a partnership between John Booth and car designer Nick Wirth, was given the go-ahead in June to enter F1 racing from next season after the sport’s governing body, the FIA, proposed capping teams' annual budgets at £40m.

Since then, Mr Crompton said Wirth had been concentrating on designing its new car, and had doubled its workforce to 100 people.