The clock is ticking on McLaren's partnership with Honda, with the Formula One team's boss saying he's been given powers to tell the Japanese engine maker that enough is enough.
Zak Brown, who replaced Ron Dennis at the helm of McLaren at the end of last year, said walking away from its tie-up with Honda was now a real option.
Honda had promised upgrades to its engine for this weekend's grand prix in Canada. But Brown told Reuters: "Honda’s working very hard but they seem a bit lost.
"We were only told recently that we wouldn’t have the upgrade coming (for Montreal)... and we don’t have a definitive timeline, which is concerning because the pain is great and we can’t sit around forever.
We were eagerly awaiting this upgrade as were our drivers and it’s a big disappointment that it’s not coming. It’s not lack of effort, but they are struggling to get it to come together.
McLaren's collaboration with Honda has spluttered ever since the pair renewed their partnership in 2015. The likes of Ayrton Senna and Alain Prost dominated the sport in the 1980s and 1990s in McLaren cars powered by the Japanese manufacturer.
But the sport's second oldest racing team has been plagued by race retirements and engine problems. McLaren was ninth out of 10 teams in 2015 and sixth out of 11 in 2016 – despite having two former World Champions in Fernando Alonso and Jenson Button driving for them.
The current team has yet to score any constructor points in the 2017 season.
Brown said the team's "preference is to win the world championship with Honda. But at some point you need to make a decision as to whether that’s achievable. And we have serious concerns."
He said: "Missing upgrades, and upgrades not delivering to the level we were told they were going to, you can only take that so long. And we’re near our limit.
The executive committee have now given us our marching orders.
Brown highlighted a number of decisions needed to be made in the next 90 days. These included a plan for the new car, seen as pivotal to giving Alonso a reason to stay with the team
He added: "There’s lots of things that go into the decision and we’re entering that window now of 'which way do you go when you come to the fork in the road'."