Silverstone's F1 future remains in doubt.

Rolling the dice on renegotiating their contract with a lower annual fee, organisers of the British grand prix have terminated the deal.

"We want to find a solution," Ross Brawn, Liberty Media's F1 sporting boss, said.

"But we are differing in our views of what's reasonable. We're not far apart but it's frustrating that we can't find a solution."

Tensions between Liberty and Silverstone ramped up even further when boss Stuart Pringle hinted that the circuit and other F1 promoters are thinking about quitting F1 completely.

"I don't think it will be the final British grand prix," Brawn responded. "Whether that's at Silverstone or not is another matter."

There are constant rumours about Liberty wanting a race in London. Brawn admitted that an event "on the periphery" of the city "could work".

Apart from Silverstone, the fate of four other significant races including Monza, Barcelona, Hockenheim and Mexico are all also in doubt.

"We don't want to lose them without a fight," Brawn said. "We are trying to find solutions, and I think we will, but circumstances change and you can't always respond to those changes.

"We will try, but we must also be fair on the other circuits."

Also outstanding is the new Concorde Agreement for 2021, but Brawn said he never expected those negotiations to be easy.

"It's a challenge, it takes time, but things are moving forward," he said.