Red Bull not mulling switch of engines from struggling Renault, says Christian Horner

From dominating the end of the V8 era with four consecutive championship doubles, Red Bull have been overtaken by Mercedes following the winter switch to V6 units and are yet to finish higher than third in the season's opening six races.

With Horner having made no secret in interviews since the start of the year that he believes Renault's power unit is holding his team's RB10 back - the Team Principal telling Sky Sports F1 in Canada on Friday that their engine remained 60bhp adrift of the class-leading Mercedes - speculation has linked Red Bull with a switch of supplier, with a link-up with Volkswagen even mooted.

However, asked if his team were contemplating a new partnership following reports that the team's home Austrian GP later this month would be the scene of discussions over their engine supply, Horner replied: "Not at this point in time, no. One hundred per cent next year we'll be powered by a Renault engine."

The Red Bull chief did add the caveat that their deal with Renault, which runs to the end of 2016, did have performance clauses attached.

"We've got a multi-year agreement with Renault, but as with any agreement there's always performance criteria associated with that," Horner added. "But we're not considering any alternatives at this point in time."

Renault declared ahead of this weekend's Montreal race that they were finally out of 'recovery mode' with their troublesome power units and could finally gain a true gauge of where their systems stack up to the competition.

Asked what percentage of extra power they were expecting to be able to unlock at one of F1's most power-hungry circuits, Horner wryly replied: "Whatever it is it's not enough!

"So whatever it is we need more of it, but the guys and girls in Viry-Chatillon in Paris are working tremendously hard behind the scenes at Renault in what they're allowed to change and do.

"Of course the technology is still very immature so hopefully there will be more steps that we can make.

"You can refine the integration of that hardware and one of the big things we're seeing this year is that fuel development as well is a critical element and that for us started later than some of our rivals because Renault were later in their development programme and running on the dynos.

"So we've got to catch up in that area as well and [fuel supplier] Total are doing a great job in finding performance."

Horner insisted that Red Bull had issued no ultimatums to their French supplier and had faith that they would eventually deliver.

"Renault fully understand the predicament that they're in. [Renault-Nissan CEO] Carlos Ghosn was in Monte Carlo to look and see for himself," the Englishman added.

"There are no ultimatums with Renault other than we want to improve as quickly as we can. We have enjoyed a great deal of success with team over the years, all our World Championships and race victories have come with Renault engines and we trust in them to sort their issues out."