The swarms of carmakers flocking to Formula E is a chance for F1 to think about going back to the future with its next engine, according to Red Bull boss Christian Horner.

Talks about the 2021 engine are already taking place, and it appears that F1 will simplify the current V6 engines by adding another turbo and reducing the hybrid elements as the sport looks to move on from the controversial 'power unit' era.

Horner told Auto Motor und Sport: "I hope we do not end up with a bad compromise.

"The manufacturers are all going to Formula E, which is their playground for future technologies. Porsche, Mercedes, Renault, Audi, Jaguar - that's already more than Formula 1 ever had.

"The cost of Formula E is 5% of a F1 budget, so what I can imagine is that the mass scale manufacturers go there and the sports car manufacturers like Ferrari, Aston Martin and Lamborghini are in F1. That's their place.

"So I see Formula 1 at a crossroads.

"If you believe the politics, we'll all be driving electric cars in 2030, so Formula 1 should be the counterpoint - pure racing, man and machine, a competition of the best drivers in the world with combustion engines."

Horner said that the ultimate call may be made by new F1 sporting boss Ross Brawn, who "needs the courage to make the right decision".

Horner added that Red Bull has done "a lot of market research" for the Aston Martin supercar project, which shows that "the overwhelming majority want a V10 or V12 and not a hybrid".