There will be a Dutch GP in "Zandvoort, or not at all".

That is the claim of Jan Lammers, a former Formula 1 driver who is now the spokesperson for a potential 2020 return to the calendar for the Dutch track.

'Lots of untold truths'

Earlier, a letter emerged that indicated a deal in principle is in place between Zandvoort and Liberty Media, with a contract to be signed no later than 31 March.

READ: Dutch circuits 'still in race' for 2020 grand prix

But Assen, another Dutch circuit, says it is still in the running.

"There are a lot of untruths around this," Lammers told Algemeen Dagblad newspaper.

"The confusion doesn't help the Dutch grand prix, but unfortunately this is the arena in which this must be played."

'Not been an option'

He insists that Assen is actually not an option.

"The promoters try to make us believe otherwise, but Assen has not been an option for some time.

"There will be a grand prix of the Netherlands in Zandvoort or not at all. Then they would go to America or Asia," said Lammers.

Assen promoter Jos Vaessen, however, insists a deal is still possible.

"Jan Lammers can say what he wants, but we are still in the picture. At the end of February we have another meeting with FOM planned," he said.