Motorsport could cease in the European Union amid an insurance crisis unless businesses and employees reply to an EU consultation by October 20, according to the Motorsport Industry Association.
The consultation is into a ruling, which applies to all 27 EU member states, made by the Court of Justice of the European Union in September 2014.
It requires compulsory unlimited third-party liability insurance to be carried by anyone using any form of motorised transport, in any location.
That includes everything from ride-on lawnmowers and tractors to single-seater and tin-top competition vehicles, even at private venues like race circuits, throughout the EU.
This means crashes in motorsport events would be treated as road traffic accidents and would involve the police, as would any road traffic collision.
Chris Aylett, chief executive officer of the MIA, is calling on any employer or business in European or UK motorsport to respond to the EU consultation and has provided guidelines to help them do so.
"This threat is real, make no mistake, it could close down all motorsport [in countries in the EU]," said Aylett.
"My appeal will safeguard jobs and the industry.
"If you want to protect your job in motorsport then make sure your employer responds before the deadline of October 20.
"The EU offers an option, known as Option 3, where their insurance requirement applies 'in traffic only'.
"If we succeed in getting this option supported then motorsport will be safe."
A common misconception in Britain's case is that its exit from the European Union, in 2019 at the earliest, will protect it from the consequences of the Motor Insurance Directive.
However, as it could be put in place within months, long before the UK leaves the EU.
"Brexit won't change things," added Aylett. "If businesses don't take positive action now then motorsport will cease and we'll all be out of a job or business.
"It's a stark choice and there's no time to waste."