Renault and Red Bull exit still believes Prost

Speculation about the future of Red Bull and Renault in Formula 1 continues to hover around the paddock.

Earlier in 2015, at the height of partner Red Bull's criticism and its performance and reliability troubles, the French carmaker made it known it was considering all options.

Now, at Monaco, the marque's famous ambassador Alain Prost admitted pulling out remains among them.

"They would like to stay, for sure," the 60-year-old Frenchman told Sky.

Prost said Renault becoming its own team again is another option, following speculation the chosen one could be Toro Rosso, the junior Red Bull outfit.

But that likelihood was recently played down by Red Bull's Dr Helmut Marko, and in Monaco, Renault's Cyril Abiteboul said the current priority is to remain "an engine supplier".

To that end, contracts with Red Bull and Toro Rosso run until the end of 2016.

"I think right now the big target is to get the engine under control, both from reliability and performance perspectives," Abiteboul said. "Once this is done we can secure some longer-term stuff."

But Prost admitted there are "other things they (Renault) can do outside" of formula one as well.

"They are also with us in Formula E," he explained, "but the first target is to see exactly what are the possibilities inside of formula one."

If the decision is ultimately to leave, it might also trigger the exits of Red Bull and Toro Rosso.

"Everything is possible," Prost acknowledged. "That would be a disaster for formula one, and that is why I hope the right decision is made, also by Red Bull.

"This situation is really a shame," he added. "Obviously I'm a Renault guy but I also know the Red Bull people and what they have achieved in F1 is amazing.

"It would be very bad to see them leaving our sport."