Honda's long-term deal with the team, which brought it back to F1 for the 2015 season, includes providing a major portion of McLaren's F1 budget, leading to suggestions that the team could not afford to end the partnership early to use a different engine supplier.

But speaking at the Italian Grand Prix ahead of McLaren taking a decision in the next week or two, executive director Zak Brown said the call – which is seemingly between Renault and Honda – for 2018 will be based purely on on-track competitiveness.

"This is the month we decide, and probably early this month is the time we're going to take a decision on our direction for next year," said Brown.

"It's very complicated, so it's a variety of pieces to the puzzle, some in our control, some not. The best thing for McLaren is to make the best sporting decision possible. The business will follow suit.

"We're here to win, that's what makes us successful, so we're going to take a sporting decision. We can't afford not to be on the podium – it's a big decision that has lots of elements to it, and economics are one.

"Fortunately we have extremely committed shareholders that we can make a sporting decision and deal with the economics. We're not financially challenged, so we can navigate any financial situation.

"We're going to sit down next week with guys that are much smarter on power units than myself and take a view on what we see [Honda's] plans are, what they have accomplished.

"Whatever we do is going to have an element of risk associated with it, but that's Formula 1.

"Right now we've got pen to paper on our 2018 chassis, but you can only go so far without knowing what power unit you'll have in the back of it."

Alonso back-up plans

McLaren remains in talks with Fernando Alonso about a deal for 2018, with the team's likely competitiveness at the centre of the Spaniard's decision.

However, Brown added that McLaren is aware it needs to have other plans in mind in case it can't convince the two-time world champion to stay.

"Fernando's not given us any ultimatum, them or us, all he wants is a competitive car," he said.

"I'll be spending more time with him this weekend, and his decision is going to be based on whether he thinks we're going to be competitive or not. He's not been engine specific in his desires.

"He hasn't signed with us yet, negotiations are on going, they are going very well, but you've got to have Plan B and C, in the event that you don't reach an agreement, and we've got those plans."

Additional reporting by Jonathan Noble