Renault forced decision upon Red Bull - Marko

When it came to the timing of Red Bull's decision to reveal its engine supplier for 2018, Renault forced the issue says Helmut Marko.

Last week , the French manufacturer insisted its partner divulge its plans before the start of the French Grand Prix weekend, but Red Bull responded that no decision would be forthcoming, at least not before next week's Austrian Grand Prix.

Ultimately however, the Milton Keynes-based team's decision came out of the blue on Tuesday.

"Actually we wanted to announce the decision after France," Red Bull's motorsport boss told Auto Bild.

"But Renault set an ultimatum that ended on Sunday. We had no choice."

• Front-row seat to Honda progress led to 'clear-cut' decision - Horner

Beyond the imperative to comply with Renault's deadline, Marko insists its decision to switch to Honda power from 2019 had already been taken before the start of the current week, and was based on the significant progress enjoyed by the Japanese manufacturer with Toro Rosso.

"The new update, which could not be properly used in Canada due to unfortunate circumstances, brought three tenths of laptime," he said.

"So the deal with Honda is extremely positive for us in every way. Sport, technical and financial."

The deal inked by Red Bull and Honda calls for the latter to supply its power unit to the former in 2019 and 2020, the two-year period preceding the introduction of Formula 1's new regulation platform.

Reports have suggested that Red Bull was reluctant to commit to Honda beyond 2020, as Porsche - often cited as a potential future partner for Red Bull in F1 - is rumored to enter the sport in 2021.

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