Renault team principal Cyril Abiteboul has stated that the French manufacturer will not accept new proposals to converge engine development in F1.
Red Bull has been arguing for the approach as it seeks to find a way forward following the announcement that its own engine supplier Honda is quitting the sport at the end of 2021.
The team is considering buying the existing hybrid power unit technology and bringing it in house, but doesn't want to get involved in a costly engine 'arms race' with Mercedes, Ferrari and Renault.
Ferrari has signalled that it might be open to a strategy of engine performance convergence, but Mercedes has called the proposal 'insulting'.
And it's clear that Abiteboul is just as unhappy with the suggestion, saying that it strikes at the very heart of what they consider Formula 1 to be all about.
“There has been a meeting where we all expressed our position,” Abiteboul told Sky Sports F1. “We’ve not changed our position.
"There is a set of regulations," he continued. “We are ready for some sort of compromise, in particular in the engine freeze because we accept convergence is happening, so spending big money is crazy.
“Having said that there is clearly a line. We will not turn our backs on 70 years of competition on engines, engine development and performance.
“For us the engine as a performance differentiator is at the core of F1. It’s what it means for us. We will not cross that line, that is very clear."
That said, Abiteboul acknowledged that the situation regarding the supply of engines in F1 is a serious matter. Red Bull has threatened to quit the sport if it can't find a suitable replacement for Honda.
“We need to find a solution for Red Bull" he said. The current sporting rules would oblige Renault to supply engines to Red Bull and its sister squad AlphaTauri if called upon.
But Red Bull split from Renault in 2018 in favour of their short lived but successful partnership with Honda, making the prospect of a shotgun reunion somewhat unappealing to Christian Horner, Helmut Marko and team owner Dietrich Mateschitz - if not quite so much to Abiteboul.
"There is already a solution in the regulation," responded Abiteboul. “We never say never. In particular we have always said we would comply with the regulations. If we have the obligation, we will do so.”
But changing the rules to allow Red Bull to create an in-house power unit development programme would be another matter entirely.
"If they can do it with Honda then all the best, but we should not go further than that," he said. "[But] if we need to write in the regulations that Red Bull should have the best engine, that’s something different. But I think this is not what’s at stake here."
In fact Abiteboul was sounding fairly upbeat about the prospect of having Red Bull back in the Renault fold again - this time as an equal partner.
"It would be good to have a partner team rather than a customer team because you see that F1 is shaping up with these groups of teams," he said. “There are probably some opportunities there whether they be financial, commercial, political or technical.
"But I think also we need to accept that train has gone," he admitted, acknowledging that recent uncertainties about Renault's own long-time future in the sport had played a part.
"There was a point when there was a lot of question marks regarding Renault’s commitment to F1," he acknowledged. "We were not really in a position to secure a long-term customer or partner team.
"[Now] we need to see when the next train is going to pass," he added. "For me, that’s not going to be massively a job added to our plan for the future.”