Formula One teams have written to the sport's powerbrokers in what they see as a final attempt to break a deadlock over next year's rules and prevent a damaging split.
"The time has come when, in the interests of the sport, we must all seek to compromise and bring an urgent conclusion to the protracted debate regarding the 2010 world championship," the Formula One Teams Association (FOTA) said.
A copy of the letter, addressed to International Automobile Federation (FIA) president Max Mosley and Formula One's commercial supremo Bernie Ecclestone, was seen by Reuters.
"We hope that you will consider that this letter represents significant movement by the teams, all of whom have clearly stated a willingness to commit to the sport until the end of 2012," it added.
"We would therefore strongly but respectfully submit that you consider these proposals and seek to avoid the potential departure from Formula One of some important teams.
"Now is the time to find a reasonable and rapid solution to the outstanding issues."
A source at one of the teams indicated that the letter represented a last attempt at compromise with a Friday deadline looming for five of the FOTA member teams to make their 2010 championship entries unconditional, with the FIA's reaction of critical importance.
FOTA suggested the deadline should be extended to July 1 to allow time for further discussions and the signing of a new confidential Concorde Agreement.
The FIA said on Tuesday that talks with the eight teams within FOTA had broken down and the 2010 rules, that include a controversial budget cap, would remain as published.
Champions Ferrari have threatened to walk out after an unbroken 60 years in Formula One if an optional 40 million pound ($65.22 million) budget cap, designed to help new teams enter and existing ones weather the credit crunch, is not scrapped.
Renault, Toyota and the two Red Bull teams have also said they cannot accept the rules.
The FIA also accused FOTA of wanting to take over the sport.
FOTA, in their letter, proposed a solution to the thorny question of policing any budget cap -- or "resource restriction" as they called it.
"We detect... that a solution might be possible based on the FOTA resource restriction proposal but with measures introduced," it said.
"We would propose in this respect that we nominate a top firm of independent accountants who will devise an audit methodology that will be implemented by all of the teams.
"This methodology and the annual results would be disclosed to the FIA... we can see no reason why such a system based on objective verification of compliance would not be acceptable to all parties."
FOTA said they welcomed the FIA's recognition that there would be only one set of rules for 2010, avoiding the two tier system that a voluntary budget cap would introduce.
Under the published regulations, teams have an option to race under a 40 million pound budget cap in exchange for greater technical freedom.
Three new teams have already been confirmed unconditionally, along with Williams and Force India, to compete under such circumstances.
FOTA said, however, that they wanted Cosworth, who will supply engines to the new teams, to retune its units so that they had no performance advantage.
In return they would "adopt one set of rules for all competitors with no adjustments for higher engine revs or anything else". In return, the teams would assist new entrants with low-cost engine gearbox packages and technical assistance.
