McLaren have confirmed they have formally ended their engine partnership with Honda, ahead of an expected switch to Renault power units.
Together McLaren and Honda dominated the sport from 1988-91, winning four consecutive driver's and constructor's titles, but their latest alliance has been doomed from the start.
Constantly playing catch-up to Mercedes, Ferrari and Renault, Honda's power units have been under-performing and unreliable, leaving Fernando Alonso Jenson Button and Stoffel Vandoorne languishing in midfield at best.
The eight-time constructor's champions have scored points at just two races this year and sit above only Sauber in the standings ahead of the Singapore Grand Prix.
A switch to more reliable engines is likely to see Alonso stick with McLaren for at least another year alongside Vandoorne.
The two-time world champion skipped the Monaco Grand Prix this year to compete at the Indianapolis 500, such was his disillusionment with the current car.
Honda are not expected to depart F1, with a deal reportedly in place for them to supply Red Bull and Toro Rosso, who will consequently lose Carlos Sainz Jr to the Renault works team.