Red Bull advisor Helmut Marko has explained why the company doubts Renault will ever close the gap to Mercedes and Ferrari.

The senior team cut their 12-year long ties with the French manufacturer at the end of the 2018 season after an increasingly difficult and tense four years during the turbo-hybrid era.

It came after initial attempts to do so failed in 2015 with their main rivals saying no and with Honda well behind, however, now the Japanese brand has caught up, they have given Red Bull an outlet to act on their belief.

“For us, it was clear at one point that Renault could not deliver us a victorious engine,” Marko told Motorsport Magazine.

“With their budget, you can not expect them to fight against Ferrari and Mercedes. It was clear that we had to do something.

“Now, for the first time in our history, we have a factory engine [in Honda]. There is a good development, and all that has happened so far is good for Red Bull Racing and Toro Rosso for next season.”

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In the months following their decision to change supplier, expectations have gradually grown as Honda have continued to improve and Red Bull has talked up their potential.

Still, there are still some questions over reliability at least after both Toro Rosso took multiple grid penalties but Marko played that all down.

“The Honda engine has been improved generally, many penalties have been taken into account because we have always wanted to bring something new,” he noted.

“According to our simulations, we would have a much better appearance with the current Honda engine but we do not need to think about that, [Renault F1 chief] Mr [Cyril] Abiteboul does, and next year we will see.”