British Grand Prix: Silverstone race 'under threat because of costs'
The future of the British Grand Prix at Silverstone could be under threat because of the "potentially ruinous risk" of staging the loss-making race.
Circuit owner the British Racing Drivers' Club (BRDC) is considering giving notice to exercise a contract-break clause at the end of 2019.
A letter written by BRDC chairman John Grant - seen by ITV News - says a decision will be made by "mid-year".
The BRDC's contract with Formula 1 runs until 2026.
Silverstone first hosted the British Grand Prix in 1950 and has been the event's permanent home since 1987.
Formula 1 chief Bernie Ecclestone told ITV News: "If they want to activate a break clause, there is nothing we can do.
"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."
Three-time world champion Sir Jackie Stewart added: "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 race track that would be able to host the British Grand Prix."
BBC Sport's chief F1 writer Andrew Benson
For anyone who has followed Formula 1 for the last decade or two, another story questioning the future of the British Grand Prix is about as surprising as cold weather in winter.
There is no doubt the British Racing Drivers' Club mean it when they say they are considering activating a break clause.
But, equally, there is no doubt that it fundamentally amounts to posturing - Silverstone does not want to lose the British Grand Prix any more than do the 140,000 fans who went there to watch it last year.
The issue is the cost of the 17-year contract - £12m in 2010; a 5% annual escalator means the race will cost nearly £17m this year and more than £26m by 2027.
This is small by comparison with Russia, which pays $50m (£40.3m) a year. It's not that far out of line with the new deal signed by Italy for €68m (£58m) over 2017-19, which averages out at £19.3m a year. But Silverstone - almost alone among grands prix - receives no government funding of any kind.
No other circuit in Britain is even remotely close to being able to replace it - so ignore any suggestions from F1 boss Bernie Ecclestone to that end.
The solution lies in new F1 owner Liberty Media, which has made it abundantly clear it wants to retain and nurture the historic European races, home of the sport's core audience, as a bedrock of its new-look F1.
Liberty will complete its takeover deal before the end of the first quarter of this year. So expect some time between then and this year's British Grand Prix on 16 July a compromise deal that revises the terms of the contract and secures the race's future.