Singapore GP: McLaren denies knowing Hamilton's gearbox was damaged

Hamilton retired from the lead of the race on lap 23 at the Marina Bay circuit after finding himself unable to select a gear.

A radio message from his team - suggesting that the outfit had done all it could in qualifying - was interpreted as a hint that the outfit knew of gearbox issues on Saturday.

However, team principal Martin Whitmarsh and sporting director Sam Michael both insist that McLaren only became aware of an issue in the few minutes before the failure.

The team is still investigating the specific part failure that stopped the gearbox working.

Michael said about suggestions the team had been aware of a problem ahead of the race: "No, Not before.

"They [gearbox warnings] have happened a number of laps before and we have started seeing some issues a few laps before [in other races]. Sometimes it can last all race and sometimes it doesn't, so we had a pretty clear warning.

"We had a full inspection after yesterday, and it wasn't related to that. I can't see any sign that it is related to that. It is extremely unlikely based on what I think the failure is in my head."

Whitmarsh added: "We saw the temperatures rise and we saw pressures increase and a few other phenomenon - so painfully we could see it coming for a few laps."

When asked if the gearbox problem could have been related to a brush that Hamilton had with a wall in qualifying, as other drivers like Bruno Senna had had to change a gearbox because of that, Whitmarsh said: "I think if you looked at [Bruno] Senna and a few others, they bounced off quite heavy.

"I have to say this morning I was talking to the guys, the wheel had two to three centimetres of scuff mark on it but it wasn't damaged.

"The rims are quite thin and brittle, and in fact the engineers performed NDT (non-destructive testing) all over the suspension.

"They were absolutely content that it was a very light brush and was not one that was going to create any damage. I don't think today had anything to do with yesterday."