Lewis Hamilton insists that it was the challenge of driving for Mercedes not the money on offer that caused him to leave the Woking family and join the Silver Arrows.

"It was one of the most difficult decisions I've faced in my life up to now," he told reporters in Suzuka ahead of this weekend's Japanese Grand Prix. "But in the end I had two offers on the table which were very similar but one was a lot more exciting."

"I've had such a great career with McLaren," he continued. "I signed for McLaren when I was thirteen and have had such an incredible journey with them. I could stay in the great car that I have, which I've worked really hard to help develop with the team, or go to a car that's not so well developed and help it. It's just a challenge."

While some claim that there is concern that Hamilton might take McLaren's secrets to Brackley, mindful of the infamous tweets he sent out over the Belgian Grand Prix weekend, the Englishman was keen to emphasise his role with the Woking outfit.

"The car that I'm in right now is a car that I've developed," he said. "Next year will be an evolution of the car that I've helped develop and that will be a championship contender.

"But we will work very, very hard to have a better year next year," he continued, referring to Mercedes, "But it takes time. You don't just arrive and things change. I think the focus is more long-term. If I can go there, help them progress, if we get some wins, if we eventually win the world championship, that's going to be an incredible feeling for all of us.

"A lot of other racing drivers, a lot of greats - Prost and Senna, they've all been with several teams," he added. "I'd been thinking for quite some time about what I wanted to do with my future, where I want to go, It's easy staying in the same place, but going somewhere else and taking on a new challenge is sometimes maybe even more exciting."

While one could almost hear Ron Dennis, who took Hamilton under his wing as a teenager, groaning at the Englishman referring to Mercedes as "we", Hamilton was keen to pay tribute to his mentor.

"McLaren will always have that place in my heart because I signed when I was 13, met Ron when I was 10. I'm so incredibly grateful to him. But we must not forget that, whilst it was Ron who signed me up, at the time it was McLaren and Mercedes, and Mercedes had to also say, 'Yes, we'll take him' so it was a joint decision by them.

"My last five years has been Mercedes and McLaren so I've always been a part of the Mercedes family but now I'm moving to be a full part of the family."