Although it has drawn short of confirming that it will be running some form of unbranded Renault power unit, team principal Christian Horner has says a deal has been finalised.

“We have an agreement for an engine for next year which we hope will be confirmed within the coming days,” said Horner. “It will have a development path – ironically of what we were trying to achieve 12 months ago.”

Horner's second reference is understood to be in relation to Renault's use of Mario Illien to help ramp up improvements in the power unit.

Renault F1 managing director Cyril Abiteboul told Motorsport.com earlier this month that it was considering Illien's involvement in a revamped F1 programme.

“We need to use all the energy and the resources that we have available,” he said. “I am absolutely not precious about where the solution is coming from – what I want is the solution. Full stop.

“There is no obligation [to take Illien], and there is nothing that is coming from us top down, from Red Bull. There is just a clear willingness to find a solution as quickly as possible.

Renault sign-off

Red Bull's announcement of its exact engine plan is believed to be on hold until Renault finalises its long-term F1 vision, as it continues discussions to try to bring about the return of a works team.

The plans for a takeover of the Lotus outfit and the return of a full manufacturer effort are yet to be signed off, and it is understood there is still no agreement in place with Bernie Ecclestone for the increase in commercial rights income that the manufacturer has been seeking.

That financial matter has been viewed as key to Renault CEO Carlos Ghosn giving the green light, and there remain concerns that without it he could yet pull the plug on it being in F1 altogether.

It is understood that fears of Renault quitting F1 were voiced in this week's F1 Commission meeting.

However, Red Bull's 2016 engine supply deal is understood to already have been agreed, which means a potential Renault withdrawal should not result in the team being left without engines.

A decision by Renault not to continue in F1 would leave the future of Lotus in doubt though, with the outfit having faced financial difficulties in the last few months.

In Abu Dhabi, its freight arrived late after delays in getting it to the track.

The team's owner Gerard Lopez suggested earlier this week that the issue with Ecclestone and FOM was key to the Renault takeover happening.

"I understand that Renault still have some things they need to clear with Formula 1 and FOM, but as far as we are concerned we are pretty much at a deal now," he said.