Sir Jackie Stewart is concerned for the future of the British Grand Prix after suggestions the race could be dropped by Silverstone.
The British Racing Drivers' Club, which owns Silverstone, is considering activating a break clause to withdraw from hosting the event due to its "potentially ruinous" costs.
Stewart, a former BRDC president and Formula One world champion who twice won at the circuit, told ITV News: "I think it's a credible threat. Not impossible for it to happen. I would be very sad if it did.
"There's no other racetrack that would be able to host the British Grand Prix."
The BRDC has a contract with Formula One to host the British Grand Prix until 2026, but could activate a break clause.
Last July's race was attended by 139,000 fans at the circuit and won by Lewis Hamilton.
ITV News said the BRDC reported it lost money hosting the event, which had cost AGBP2million ($A3.4 million) to stage a year earlier.
Silverstone has hosted the British Grand Prix since 1987 and there have been prior rows with Formula One supremo Bernie Ecclestone on the staging of the event.
Ecclestone told ITV News that he had received other expressions of interest to host the race.
"If they want to activate a break clause, there is nothing we can do," he said.
"Two other tracks have contacted us and we are keen to keep a British Grand Prix, there is no doubt about it, we want to have one. As far as Silverstone is concerned, it's not in our hands."
