Niki Lauda is confident that Lewis Hamilton remains committed to signing a new deal with Mercedes, but suggested the world champion's inconsistent start to the 2018 season has led to protracted negotiations. Hamilton's current deal runs out at the end of this year.

Mercedes, and even Hamilton himself, had previously spoken with an assuredness that a new deal would be signed before the season started last month.

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However, fresh terms remain unsigned, although it is understood that a contract has been drawn up worth £40million a year - which would make him Britain's best-paid athlete.

As 2018 has begun in frustrating style for Mercedes, who remain winless after three races, Lauda says the exact details remain in flux, but the end result will remain the same.

He told Auto Motor und Sport: "It's just about the details. Lewis will continue to drive for us.

"Depending on the mood, it is sometimes more or less expensive.

"It always depends on how the last race went. But the money is not a problem. We agree in principle."

Hamilton has previously suggested that waiting for Liberty Media to offer more details on their vision for F1 in 2021 is behind the delay over signing a new deal.

"It's always good to wait to hear some of those and see the future of Formula 1," he said earlier this month.

"For sure that could or could not have an impact on decisions we make in terms of length or whatever we end up doing in Formula 1.

"The next contract is probably the most important one of my career, this decision I make.

"So the length, your decision how long you want to commit to being in Formula 1 is becoming more and more important I think for me, being that I'm at the latter end of my career."