Almost within sight of the chequered flag in Barcelona, the 2008 world champion's McLaren speared into a barrier after a sudden tyre failure, costing him second place both in the race and in the world championship standings.

The shattered remains of Lewis Hamilton's front left corner is being rushed back to Woking for analysis.

Almost within sight of the chequered flag in Barcelona, the 2008 world champion's McLaren speared into a barrier after a sudden tyre failure, costing him second place both in the race and in the world championship standings.

Team boss Martin Whitmarsh immediately speculated that "debris" probably caused the problem, while Bridgestone said its initial impression was that "this was not caused by a tyre issue".

"We are working closely with McLaren to understand what happened," added the Japanese supplier's Hirohide Hamashima.

As the sun rises again in Europe on Monday morning, the leading theory now is that a stone became stuck in the wheel rim.

After qualifying, Rubens Barrichello took photos with his mobile phone camera of his FW32 and his helmet, so amazed was he about the damage caused by flying stones.

And he told Germany's Auto Motor und Sport that he had to nurse his vibrating Williams to the chequered flag after feeling a "strong shock" on the left front.

"We had to slow him down to ensure we didn't have a problem with the tyres," confirmed technical director Sam Michael. "We'll be looking into that for the next race."

Barrichello suspects a stone got stuck in the wheel rim, and a similar cause was also not being ruled out to explain Sebastian Vettel's brake problem.

After the Red Bull was inspected, Christian Horner revealed that the brake disc "was a bit damaged".

"We will only know for sure in the factory," added the Briton.