Formula 1 risks driving Renault out of the sport if a push to relax next year's engine freeze is not accepted, Red Bull boss Christian Horner has warned.
As Motorsport.com revealed last week, Mercedes' rivals are pushing to allow in-season development to continue next year after the loophole was closed off by the FIA for 2016.
But with Mercedes reluctant to allow scope for its rivals to continue working on power units in-season for fear of costs escalating, there is the prospect that manufacturers like Renault and Honda that are struggling could face never having the opportunity to improve.
Horner suggests that such a scenario would be unacceptable for Renault, and thinks that Mercedes needs to think very carefully about what is best for F1 if it intends to block the rule change as it did 12 months ago.
Time to grow up
When asked about getting Mercedes to change its mind, Horner said: "They don't have to obviously, but the situation is we are at a precarious point in terms of Renault's commitment to the future.
"If you are effectively shutting that down in February, you are almost waving goodbye to them.
"So [Mercedes] need to have a bit of a grown-up think about it. And the FIA as well to say what is in the best interests of F1.
"If F1 can afford to lose an engine manufacturer, then stick to February 28."
The 2016 regulations state that engine designs will be frozen from February 28 next year – meaning no further performance improvements will be allowed after that date.
Horner has made it clear that such a scenario would make it almost impossible for Renault to see a positive future in F1.
"From Renault's perspective, it is the worst thing for them," he said. "Then, the engines are effectively frozen forever after.
"If you have missed it by February 28, the scale of difference is unachievable in that timeframe.
"So really as these regulations still are relatively immature, it would be sensible, as this year, to allow development in the season."