Silverstone is in danger of losing its place on the MotoGP calendar, with a draft 2018 schedule issued by the series listing the venue for the British Grand Prix as 'TBC'.
The Northamptonshire track has hosted Britain's MotoGP round since 2010 after the event moved away from long-time home Donington Park, which held the race from 1987 to 2009.
Silverstone made a deal with the Circuit of Wales to continue holding the event after the proposed Ebbw Vale-based facility signed a five-year deal with series promoter Dorna covering 2015-19.
But this agreement has been effectively nullified by CoW's inability to secure the government guarantees it needed to be able to commence construction, leaving Silverstone's future hanging in the balance.
Dorna is in negotiations with both Silverstone and Donington for 2018 and beyond, a situation reflected by the venue for the British round being listed as 'TBC' on a draft calendar issued on Wednesday.
The 2018 schedule contains few other surprises, with Thailand's Buriram Circuit the only new addition.
It has been given a provisional date of October 7, two weeks before the start of the triple-header comprising the Motegi, Phillip Island and Sepang rounds.
As previously reported by Motorsport.com, the season is due for a slightly earlier start in 2018, with the Qatar season-opener set to take place on March 18.
The Barcelona date has been pushed back a week to June 17, with the subsequent Assen and Sachsenring rounds also taking place later than in 2017 - shortening the summer break to three weeks.
Thailand's arrival also means the season will conclude one week later, on November 18, in Valencia.
Draft 2018 MotoGP calendar:
|April 8||Termas de Rio Hondo|
|May 20||Le Mans|
|August 12||Red Bull Ring|
|October 28||Phillip Island|