With McLaren and Honda's relationship increasingly strained on the back of a disappointing season, it is no secret that the Woking-based team is chasing an alternative power supplier for next year.

But its hopes of doing so rest on convincing Honda to form an alliance with Toro Rosso, which would then free up the Faenza-based team's supply of Renaults.

Toro Rosso had wanted a decision from Honda about a 2018 deal by the end of the Italian Grand Prix weekend.

However, despite a series of meetings at Monza involving McLaren, Honda, Renault, Toro Rosso and Red Bull representatives, no resolution to the situation was sorted.

But with the FIA and F1 chiefs stepping in to help try to move things forward, it is looking increasingly likely that the final pieces of the jigsaw will fall in to place over the next 48 hours for the deal to go through.

McLaren racing director Eric Boullier conceded that matters were not particularly straightforward, but he remained hopeful that a solution that would keep Honda in F1 can be sorted.

"It is complicated because you want to do the best for F1 as well, it is not only for McLaren," explained the Frenchman.

"Whatever will happen, and it is a good collaborative work with all the parties in the paddock, we all try to make the best of the situation. But I will not comment more than this."

McLaren executive director Zak Brown said that nothing was yet guaranteed, despite the indications that a deal could be closed once the Honda and Toro Rosso situation was finalised.

"There's a couple of different scenarios," he told Motorsport.com. "That's the scenario that everyone's waiting to hear, if something's happened with those two. But that's not the only scenario."

Beyond the question of supply, there are also understood to be issues relating to compensation payments for the early ending of contracts.

Furthermore, one scenario that has been suggested is that Renault wants to take Carlos Sainz off Toro Rosso's hands in exchange for an early end to its contract with the team.

Although nothing was yet lined up, Brown remained hopeful that an outcome could be delivered that would suit everyone.

"Yeah, ideal scenario everyone's smiling at the end. I think it's possible," he said. "Toro Rosso need to make it…

"They're probably going to be the ones… There was this reported deadline, don't know about that, they've not told me about it. But it's next week, so everything hinges on that."

Boullier admitted too that things were now getting late for McLaren to know its future engine supplier.

"We need to know what we do and where we go because there is now a timing issue with the next year's car design," he said.