A split has emerged between Formula 1 teams as talks over the future of the sport reach a critical stage.
Half the teams object to plans to postpone the finalisation of a budget cap for 2021 from June until October.
Alfa Romeo, McLaren, Racing Point, Renault and Williams believe it is a back-door attempt by big teams to water down cost restrictions.
But Mercedes and Ferrari reject the claim and say the proposed 2021 rules are “immature” and need more work.
The stance of the five teams puts governing body the FIA and Formula 1 in a difficult position because regulations dictate that the 2021 rules have to be finalised by the end of this month, unless they can secure support from all the teams for a delay.
And all agree that the sporting and technical rules are not ready for publication.
A meeting is planned between the various parties on Thursday, before a meeting of the FIA World Council, F1’s legislative body, on Friday, which has to decide what to do about publication of the rules.
McLaren chief executive officer Zak Brown, speaking exclusively to BBC Sport, said: “We want what will bring the best balance to the sport.
“As a sport we spend way more money than we need to go racing and put on a good show for the fans. We’re one of the few industries that hasn’t adjusted to today’s economic realities and as a major sport we have more financial imbalance among competitors than any other.
“We need to push forward so that every team has a reasonable opportunity to be competitive. We need to lock down the future of the sport before it’s too late.”
Enforcing an effective budget cap, as well as creating a more equitable split in revenues among the teams, is a matter of critical importance for the smaller outfits because F1 has turned into a two-tier championship.
Mercedes, Ferrari and Red Bull have budgets in the region of $300m-400m (£236m-315m) a year. The other teams’ budgets range from about $120m-210m (£94m-165m) and as a result they cannot hope to compete.
This locks in a situation where the smaller teams can never hope to win a race – and can only manage a podium finish in races where there are lots of incidents.
Renault, McLaren, Racing Point, Alfa Romeo and Williams feel that the current arrangements for the budget cap in 2021 are acceptable and do not want to open the door to any further changes.
The original plan was for the cap to be set at $150m a year, but after more than a year of talks that number has gone up to $175m, in addition to several exclusions.
Drivers, the salaries of the three highest paid executives, engine bills, marketing and hospitality, and race weekend travel and accommodation are not included in the cap. That could amount to as much as $75m extra, depending on the team.
The five would have preferred to have the figure set at $150m, but have agreed to the compromise number of $175m with the concession that it is introduced in 2021. Previously, a glide path down to the ultimate cap over three years from 2021 to 2023 had been planned.
But the teams will not sign off on a delay to the sporting and technical regulations without the budget cap being secured this month.