Martin Whitmarsh believes his McLaren team put forward a higher contract offer than any driver receives on the grid when it attempted to keep Lewis Hamilton on board for 2013.

Last week Hamilton made the decision to leave McLaren for Mercedes after being at the team since he was 13 years old. McLaren reportedly upped its financial offer in the final week of negotiations and Whitmarsh believes the terms were higher than any other contract in F1.

"I think Lewis is a top-flight driver and we didn't underestimate his attractiveness to others in Formula One," he told the Vodafone McLaren Mercedes phone-in. "I think we knew that Lewis would be in demand and that's why we made him an offer.

"The offer that we made was higher, I believe, than any other driver in Formula One is currently receiving or will receive next year. I think it was a good offer, but clearly we had to look at some alternatives because we recognised that there was a serious threat."

Whitmarsh said he had no regrets about the way McLaren approached the contract talks with Hamilton and his management company XIX Entertainment.

"We had a lot of conversations with Lewis's management team," he said. "I don't think I have any particular regrets. I think that we made a very good and serious offer and proposition, and ultimately of course we weren't able to agree terms. I'm probably not the best person to be objective about it and looking back at regrets is not something you get much time for in Formula One.

"We put a lot of effort in to trying to keep Lewis. Clearly he's a great asset to any team. We made a big effort but I think ultimately Lewis had to make a decision and he made one and we must now look forward."

He reiterated his belief that McLaren's 2012 title bid with Hamilton will not suffer as a result.

"We've got six races to go, we've got a competitive car, two competitive race drivers and two championships that are still in our sights," Whitmarsh added. "I think what we are all hoping - Lewis and the team - is that we actually really focus now. In one sense there is some clarity; we are committed to working as hard as we car to allow Lewis every opportunity to achieve a drivers' world championship and at the same time I believe Lewis is totally committed to working hard with the team to contribute to our assault on the constructors' championship."