Red Bull are without an engine deal for next season after splitting from Renault

Red Bull will decide whether or not to stay in F1 by the end of October, owner Dietrich Mateschitz has confirmed.

The former world champions, along with junior outfit Toro Rosso, are threatening to leave the sport unless they secure a supply of 'competitive' engines for next season.

Exasperated by the inadequacies of the underpowered and unreliable power units provided by Renault, Red Bull will split from their long-time providers at the end of 2015 but are yet to agree an alternative deal with any of the remaining three engine providers on the grid. While Mercedes, determined to retain their competitive advantage over the rest of the field, have formally rejected Red Bull's request for a supply, Honda will remain McLaren's exclusive partners in 2016, and doubts continue about the feasibility and details of a partnership with Ferrari.

In addition to building for the engines for their own eponymous works team, Ferrari are already contracted to power both Haas and Sauber in 2016, and talks between Red Bull and Ferrari are believed to have floundered on suggestions that the Milton Keynes outfit would only be given 2015-spec engines.

With the clock ticking on the build process for 2016, and team boss Christian Horner warning that his team are already behind schedule on the construction of next year's car, an October deadline has now been set for the bail-out deal without which Red Bull will walk away from the sport.

"We strive to get motors, but we get none - at least not the one we want," Mateschitz told Speedweek magazine. Asked how long the team were prepared to wait for a deal, Mateschitz replied: "Sometime in late October."

Speedweek is owned by Red Bull and has regularly been used by Mateschitz as a mouthpiece for his mounting frustrations since F1's new turbo age saw engine power become the dominant performance differential. In a furious rebuke of Renault, the billionaire told the magazine in June that "they take from us not only time and money, but also the will and motivation".

It's understood that Red Bull's official request to Mercedes for an alternative supply was issued just two weeks later at the British GP in early July.

Dietrich Mateschitz (right) has repeatedly warned that Red Bull could quit F1 at the end of 2015

According to the publication, Red Bull have paid Renault 54 million euros a year for a supply of engines for both their teams, with the outlay part of an annual F1 budget of between 300 and 400 million euros.

In a further ominous warning to F1 of the gravity of Red Bull's threat to quit, the group are described by Speedweek as a 'drinks producer, no eternal Formula 1 team like Williams or McLaren, and not a car manufacturer like Ferrari, Mercedes, Renault or Honda. The Formula 1 involvement is for the Austrians a marketing tool, a vehicle for global image advertising.'

And good publicity, like engines, is currently in short supply for Red Bull.

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