Vettel damages Red Bull

The Spaniard's best lap of a minute 38.670 seconds was set on intermediate tyres during a changeable and eventful session that featured a red flag because of Vettel's accident.

Mercedes drivers Nico Rosberg and Michael Schumacher were second and third fastest ahead of the Renault's of Nick Heidfeld and Vitaly Petrov.

Sauber's Kamui Kobayashi, typically spectacular, was sixth in the Sauber ahead of Felipe Massa, Toro Rosso Friday man Daniel Ricciardo and his team-mate Sebastien Buemi and Force India's Nico Hulkenberg.

The rain offered the first opportunity for the drivers and teams to learn about Pirelli's wet weather tyres in competition conditions, but as usual it was a while before anyone set a realistic time.

Just after half an hour Alonso set the first representative lap of the frontrunners with a 1:40.897, on his fifth lap on full wet tyres. But already the Spaniard was indicating over the radio that he had already got the best from the Pirelli's grip window.

A couple of minutes later, Nico Rosberg moved the target time down to 1:40.072 - 0.8s faster than Alonso.

Mark Webber emerged from the pits just after halfway through the 90 minute session - the first driver to give the intermediates a try, but his lap was only good enough for tenth and he quickly returned to the pits.

Up to this point the rain had been steady, but light, then with 40 minutes to go it began to fall harder again and Rosberg told his team that aquaplaning was occurring at turns two and 11.

That didn't stop Alonso moving back to the top of the times with a 1:38.670, and he was on intermediates.

Meanwhile several drivers ignored Rosberg's advice and ran wide at the fast turn 11 - a list that included Timo Glock, Sebastien Buemi, Schumacher, Felipe Massa and Vettel who finally decided to venture on to the track having missed the driest period of running.

Not long after though, the world champion was in the barriers having given them a hefty whack when he ran wide at turn eight. So hefty in fact that he brought out the red flag for 10 minutes - leaving just 15 minutes to go.

But the track was now thoroughly wet and those that ventured out discovered it had lost a couple of seconds in pace.

Both rookies Pastor Maldonado and Paul di Resta, as well as Schumacher all registered a spin each. Maldonado actually had two incidents the second of which appeared to damage his car.

McLaren drivers Jenson Button and Lewis Hamilton did not complete any significant running, with the latter not even setting a time.