Red Bull motorsports consultant Dr Helmut Marko has warned that the team could quit Formula 1 if its new engine partnership with Honda fails to deliver on expectations.
Red Bull has been frustrated with the engine situation in F1 for several years. It had announced that it was splitting from Renault in 2015 only to roll back on the decision when it was unable to get a competitive deal with another manufacturer.
However the team has now finally made the break and will partner with Honda in 2019. The Japanese company already provides power units to the junior Toro Rosso squad, after three years of disappointment working with McLaren.
“The cooperation with Honda has been running very well with Toro Rosso so far,” Marko told Speedweek.
“After the McLaren disaster, Honda was close to a departure from Formula 1 at the end of 2017.
"We really had to convince the Japanese in intensive conversations that they could resume with us to start.”
Marko says that it's crucial for both parties that the new collaboration with Honda works. Another flop might lead not just to Honda quitting the sport - but Red Bull as well.
“We are pleased with the great cooperation with Honda for the coming years," he said.
"[But] if this cooperation, for whatever reason, does not work as expected, then Red Bull will leave Formula 1.
"As Mercedes and Ferrari do not want to supply Red Bull and no new manufacturer is coming, only the exit remains," Marko told Salzburger Nachrichten.
Honda's deal to supply Red Bull lasts two years, taking it through to the end of the 2020 season. That's when the current agreements about how the way the sport is run - including technical and engine specifications - are due to expire.
It means that Red Bull owner Dietrich Mateschitz really could pull the team out of F1 at that point, after 16 years in the sport.
The team made its first appearance in 2005 and went on to win the constructors championship four years in succession between 2010 and 2013. It was also runner up in 2009, 2014 and 2016.
But with the rise of Mercedes and a surge in form from Ferrari, the team has been relegated to third place in the last two campaigns and looks to be heading for a repeat in 2018.
In 14 races so far this year, Red Bull has taken three wins at China, Monaco and its home race in Austria. But it has also been plagued by retirements, many of which it has blamed on the reliability of its TAG Heuer-branded power units.
Marko previously said that he was confident that Honda will be at least a match for the team's existing power units by the end of the year, and predicted that it will be ahead of Renault in 2019.