Red Bull has decided to switch to Honda Formula 1 engines next year, high level sources have revealed, with confirmation of the move likely ahead of this weekend's French Grand Prix.
Although the Milton Keynes-based team had been expected to wait until the Austrian GP to make its final decision on the 2019 engine call, indications now suggest senior management has made its mind up.
Following close evaluation of the performance steps made by both car manufacturers over the Canadian GP weekend, and well aware that Renault could not guarantee it could keep its engine supply offer open, Red Bull is set on committing to Honda.
It is understood its decision was communicated to external parties late on Monday night.
Red Bull was unavailable for comment, and it is unclear when the move will be made official, but there are suggestions it could come before this weekend's race at Paul Ricard.
Red Bull has elected, after more than a decade with Renault that yielded all its world championships during the V8 engine era, to throw its focus in with the Japanese manufacturer.
The move will come as a blow to Renault which had been hoping to keep Red Bull on board to act as a benchmark for its own works team.
Speaking at last weekend's Canadian GP, Renault F1 managing director Cyril Abiteboul said: "I understand what they are looking to get.
"They are looking to the technical and commercial side, because it is clearly different remaining a customer and partner of Renault versus becoming a works team with Honda.
"I appreciate that. But frankly, as far as I am concerned, they have a chance with us to become world champion again. I cannot say for Honda."
Honda has made progress this year with Toro Rosso, following its split from McLaren at the end of last year.
An upgrade at the Canadian Grand Prix produced a significant performance step, despite Pierre Gasly needing a replacement engine following a problem in final practice.