Formula 1's desire to hold a race in London is causing Silverstone to reconsider plans to sign a new contract for the British Grand Prix.
Silverstone's contract runs out after next month's race and it had agreed terms on a new deal before F1 told it of plans to hold a race in the Docklands area of east London.
Silverstone managing director Stuart Pringle said the plan "significantly increases the risk" in holding the race but added that talks are ongoing and the parties hope for a resolution.
An F1 spokesman said: "We are still in constructive talks with Silverstone."
The concern at Silverstone is that a London Grand Prix could reduce its attendance figure sufficiently to make the race unviable.
The track, which first hosted the British Grand Prix in 1948 and held the first World Championship F1 event in 1950, is out of contract this season because it activated a break clause in a contract that would have otherwise run to 2026 on the basis that it could not afford the escalating fees.
In an exclusive interview, Pringle told BBC Sport: "F1 have admitted to us for the first time that they want to have a race in London. That's a material change because it's different to previous arrangements and Britain is not a very big island and it's a commercial concern.
"Throughout this process we have sought to manage the significant risk that comes with promoting an F1 race and this does nothing to reduce it.
"In fact, it significantly increases the risk to Silverstone that only a few short years ago was nearly obliterated by its commitment to F1 and trying to maintain a British Grand Prix. We metaphorically and literally cannot afford to go back to that position.
"But we are still very much talking. They've always said they want a British Grand Prix at Silverstone and we've always said we want to host one."
Silverstone believes a London event would necessarily have to be held relatively close to its own race in the schedule because the British weather means there is a relatively short window in which to hold the race.
Silverstone is only 80 miles from central London so there is a risk that a race in the capital could affect attendance, which would increase the financial risk.
Silverstone has always said it wants to host the British Grand Prix but that it will not do so if threatens the financial future of the track.
It is owned by the British Racing Drivers' Club, an organisation whose main aim is to promote and sustain motorsport in the UK. It sees itself as the 'guardian of British motorsport' and aims to foster the country's racing talent.
F1 would not comment directly on its desire for a London Grand Prix, but its managing director Ross Brawn said at a news conference in March: "London would be a different race than the British GP. It is a city race. There is a place for both.
"But I don't think it's feasible to have a London race in the middle of London, unfortunately - the chaos and impact it would have would be too severe - but on the periphery of London there are a number of areas that could work. I don't see it as it would necessarily replace the British GP; it would be the London GP."