No Red Bull 2019 engine decision until June

Red Bull will make no final decision about its Formula 1 power unit plans for 2019 until next month at the earliest, according to team principal Christian Horner.

Red Bull's current deal with long-term engine supplier Renault expires at the end of the 2018 season, with the two parties having experienced a rocky partnership under the V6 hybrid regulations introduced in 2014.

Red Bull has confirmed publicly it has held talks with Honda about a possible deal for 2019. The Japanese manufacturer currently supplies Red Bull B-team Toro Rosso with engines, appearing to act as a precursor to a possible expanded deal in the future.

Renault said in pre-season that it wanted Red Bull to take a decision by the FIA's deadline for notice of supply, which is May 15, but Horner confirmed on Sky Sports F1 on Friday that a call would be made beyond this date, despite Renault F1 chief Cyril Abiteboul saying the team needed to know how many teams it would be supplying in order to account for part numbers.

"It certainly won’t be in May," Horner said.

"Cyril’s comments about bits? Well he is always short of bits anyway, so putting in an order for a few more parts isn’t going to do them any harm.

"Our decision-making will be at the earliest is in June. You always want a clearer picture before you make a commitment. That is what we are trying to achieve."

Renault engine boss Remi Taffin said that while the bulk of decisions regarding contracts lay with Abiteboul, he agreed that a certain level of notice was required from Red Bull over its intentions for next year.

"Obviously there are some deadlines, which is simply based on the fact that we have to order parts," Taffin said.

"As a starting point, we know that by the end of this months we would have to start buying some parts to supply as many teams as we would have to for next year. So that is one of our technical deadlines.

"Then the rest, as I said, is all about having a contract or not with them, which is obviously on their side."

Honda's Toyoharu Tanabe added that following the preliminary talks in Baku two weeks ago, a deal with Red Bull remained "under discussion", but could not give a date which an agreement would need to be confirmed by.