Fernando Alonso has said that even a seat at Mercedes or Red Bull would not convince him to stay in F1 if next year's cars do not excite him.
The Spaniard has warned repeatedly that his entire F1 career is riding on the 2017 regulations, because he is turned off by the current tyre and fuel-saving formula.
"I have a contract for next season," Alonso told Finnish newspaper Turun Sanomat, "and I'm sure that McLaren will build a good car and Honda will be more competitive than at present. So the only question mark is if I will enjoy driving the new kind of cars.
"If the rules had stayed the same, where you have to save everything from the first lap of the race, next year would have been my last in F1.
"I would go even further and say that even if I win next year's championship, but I don't enjoy driving the cars, I finish my career."
Even in the case that he is offered a top Mercedes or Red Bull seat for 2018, Alonso said that is not among his criteria for staying on the grid beyond his 36th birthday.
"First I don't think they will, because they already have drivers for the next two years. At this moment, the idea of having the best car or changing the team does not motivate me," he insisted.
The 2016 championship continues this weekend with the Mexican Grand Prix.