McLaren is currently weighing up whether to commit to Honda for another year or make the switch to another supplier – with Renault now its only realistic option if it wants to change.

It has been clear for some time that Renault is reluctant to expand to a fourth supply for 2018, with it currently committed to Red Bull, Toro Rosso and its own works team already.

While there remains an outside chance that Toro Rosso could end up switching to Honda if talks do accelerate, it is looking increasingly likely that this will not happen.

Speaking at the Belgian Grand Prix, Renault F1 managing director Cyril Abiteboul admitted that there had been discussions but suggested that a deal was not looking likely.

"The situation is we have a multi-year contract with Red Bull Racing and Toro Rosso," said Abiteboul.

"So frankly we are open to discussions. I can confirm there have been discussions with McLaren, but right now there is a restriction in the regulation if we wanted to supply more than three teams.

"In addition to that, I don't think it would be reasonable to believe that we could supply more than three without degrading the level of service, the quality of service, for the other teams.

"We have had discussions and frankly, we have [current] contracts in place. We value the relationship with Red Bull. It is a long-standing relationship and we would like to carry this relationship until 2020, but if there is something to be done [elsewhere], why not?

"But right now I understand things are very quiet and they are not necessarily pushing for anything."

Motorsport.com revealed earlier this week that McLaren has been left facing a dilemma over its engine choice, because work from consultants Ilmor had helped Honda to good gains on the dyno – lifting hopes of a good step forward with form in 2018.