A group of Formula 1 race promoters are preparing to confront the sport's owner Liberty Media.
Led by Silverstone, the race officials are angry with Liberty over the handling of their contracts, with the Daily Mail reporting that they are threatening to leave the calendar.
'Everyone is disgruntled'
The newspaper said the promoters met for a meeting in London to discuss the situation.
"Everyone is disgruntled. Liberty's ideas are disjointed," said Stuart Pringle, the Silverstone boss and head of the F1 promoters' group.
This year, the race contracts of Silverstone, Monza, Barcelona, Hockenheim and Mexico all expire.
"We have all been compliant and quiet hitherto, but we have great concerns about the future health of the sport under the people who run it now," Pringle added.
He admitted they are particularly angry about Liberty's handling of a potential race in Miami, even though a deal was not ultimately done.
"Miami are seemingly getting a free deal. That has not gone down well with anyone, not least with the guys at Austin, Texas, who are working hard to make their race pay.
"If this continues, formula one will be racing on second-rate circuits, if any at all," said Pringle.