McLaren drivers summoned by stewards

Many of the front-runners completed their Q3 laps earlier than normal because of the threat of rain, and then slowed down on their in-laps to conserve fuel for the first stint of the race.

But other drivers were still completing their flying laps as the leading pole contenders backed off, and both Alonso and Heidfeld felt they had been impeded.

Heidfeld singled out the two McLarens for particular criticism.

"The first corners of my last lap went smoothly, but then there were several cars driving very slowly on their in-laps," said the BMW driver.

"Apparently they had no information that the qualifying was still going on. Before Turn 4 I lost a lot of time because both McLarens were cruising on the racing line.

"I think this has cost me about two tenths of a second, which would have meant being third instead of seventh. I just couldn't drive on the line I wanted and, even more importantly, could not brake were I wanted."