Renault’s 2019 power units could end up propelling them – and McLaren – into contention with the top three in the Constructors’ Championship with the improvements that have been made.

The 2018 power units failed to show enough improvement to keep Red Bull as a customer, with the unreliability of their engines hampering the Milton Keynes-based outfit’s title charge.

They decided to end their decade-long association with Renault in favour of Honda as a result, despite McLaren making the opposite swap just 12 months earlier.

Therefore, the French manufacturers will only be powering their works team, who has just acquired Daniel Ricciardo, and McLaren, who finally have cause for “cautious optimism” after being told Renault has found “a lot of kilowatts” in the development of their 2019 engine.

"They are telling us that they are very pleased with their winter progress," said McLaren CEO Zak Brown said. "They have found a lot of kilowatts, and think they will be in the ballpark.

"It is not appropriate for me to quote the numbers they have given us, but I think they feel they are going to be very competitive next year.

"There is a lot of cautious optimism, but we clearly don't want to get ahead of ourselves. We have done that before and we are not going to make the same mistake twice.

"So it is a very head down approach. Development is going well, and we are on track with what we are wanting to achieve.

"But ultimately obviously we have no idea where the competition is, other than speculating. Everyone plants their different stories: they either want to under play it or over play it. I don't think we will obviously know until we get to Barcelona.

"We are pleased with the progress we have made. We have done things differently, everyone is working well together, so it feels like a more quiet confidence."