McLaren Executive Director Zak Brown has revealed the British team began to question their future partnership with Honda in February during the miserable pre-season testing.

On Friday, the anticipated split between the two parties was confirmed as McLaren and Renault announced a new wide-ranging partnership from next year, while Toro Rosso revealed they have signed a three-year engine deal with Honda.

It spelled the end of a saga which has seen growing frustration from McLaren at the inability of their soon-to-be former partner to be competitive against their rivals, with drivers Fernando Alonso and Stoffel Vandoorne taking engine penalties from as early as Bahrain and only a strong weekend in Hungary lifting them off the bottom of the Constructors' Championship.

"I don't think there was a specific tipping point, other than we knew we were in trouble in pre-season testing," said Brown in Singapore. "We needed to improve upon our 2016 results, so we knew we were in trouble then.

"We've spent quite a bit of time, most of it in the public domain, trying to find ways to get Honda competitive with us. We ultimately couldn't get there in the end, but it's great that they're staying in the sport."

There had been some improvement towards the end of last year, with Alonso scoring a number of points results, however, a decision by Honda to overhaul the design of their power unit, believing it offers greater long-term development potential, led to the step back this year as flaws with their concept only emerged when track testing began.

That led to speculation McLaren was seeking a return to Mercedes power for next year and even a seemingly unfathomable deal with Ferrari was mentioned before both suppliers said no.

That would only leave Renault as an alternative for 2018 and, thanks to the eventual agreement with Red Bull that will see Toro Rosso drop the French manufacturer for Honda and Carlos Sainz switch to the Enstone team on a loan, a deal was able to the done.

"I want to thank a lot of people, because this has been quite a public process, involved a lot of people, and required a lot of cooperation to get the outcome that I think was best for the sport," Brown added.

"Starting with the McLaren fans, they've been unbelievably supportive as we've been through a difficult three years.

'Then it took the collaboration of Christian [Horner], Toro Rosso and Red Bull. Then the FIA, and Ross [Brawn] and Chase [Carey] – there were a lot of people that needed to come together to make this happen.

"Last but not least, Honda has been a great partner. Obviously, we haven't had the on-track results that we'd hoped for, but they certainly gave it everything they've got. We felt that it was time to move on.

"I'm looking forward to next year. We're very excited to be partnering with Renault and all the work that Cyril [Abiteboul] and his team put in."