Red Bull owner Dietrich Mateschitz's patience is running thin in light of the engine supply issues associated with both of his Formula 1 teams.
In an interview with Red Bull's own publication Speedweek, the Austrian billionaire underlined the fact that both Red Bull Racing and Toro Rosso have yet to finalise a power unit agreement for 2016.
The quandary has led to uncertainties regarding the very presence of Red Bull in Grand Prix racing next year, and when asked about its 2016 prospects, Mateschitz said nothing to alleviate fears of its complete withdrawal from the sport.
"I cannot give a definite answer to that question because we still don’t know if we will get an engine and what else is planned for the future," Mateschitz told Speedweek.
"But at some point even we’ve had enough."
It is expected that resumed talks between Renault and Red Bull will lead to a deal between the two parties by which the Milton Keynes outfit would run an unbranded power unit supplied by the French manufacturer.
But time is of the essence according to Red Bull team principal Christian Horner who stressed in Brazil the necessity to get clarification within weeks on its engine plans in order to remain within the practical deadline window.
"At the moment we are right on the limit to be at the first test," Horner said.
"The team in Milton Keynes have demonstrated their ability to work to massively tight deadlines, and I am sure we will be able to meet whatever targets we need to, as long as we come to a decision in the next couple of weeks."
Technical feature: Exclusive pictures of the Ferrari power unit
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