SILVERSTONE, England (AFP) - World championship leader Felipe Massa topped the times but also suffered a high speed crash in an eventful free practice session at Silverstone on Friday morning.

The Brazilian Ferrari driver completed only eight laps in the first session ahead of Sunday's British Grand Prix, but none of his title rivals could match the lap of 1min 19.575sec he set just before slamming his car into the crash barriers.

McLaren's Heikki Kovalainen was second fastest just ahead of his British teammate Lewis Hamilton.

Kimi Raikkonen was fourth fastest in the second Ferrari with BMW Sauber's Polish ace Robert Kubica fifth and Fernando Alonso of Renault sixth.

The hour-and-a-half session began in bright yet cloudy conditions. German Toro Rosso driver Sebastian Vettel was the first man to record a lap time and only four other drivers ventured out in a quiet first half hour.

Two of them, Kazuki Nakajima of Williams and Adrian Sutil of Force India, suffered early 'moments' but both managed to correct their respective slides before any damage was done.

As more cars began to take to the track the Toyotas of Italian Jarno Trulli and German Timo Glock moved to the top of the times only to be quickly usurped by Raikkonen.

Silverstone is one of the Finnish world champion's favoured circuits and after winning in Britain last year he is sure to be a major contender once again in Sunday's race.

Another Finn, Kovalainen, was next to move to the summit of the timesheet with a lap of 1:19.919, marginally quicker than Hamilton's initial efforts.

Massa was the last of the title contenders to attempt a flying lap but when he did emerge he immediately set the quickest time of the session.

Then with 35 minutes of practice remaining, former world champion Alonso was forced to pull over with smoke billowing from the rear of his Renault.

As Alonso walked back to the garage, the unfortunate Massa ran through the oil that had leaked from the Spaniard's car and completely lost control of his Ferrari, slipping off the track and hitting the barriers extremely hard.

The Brazilian world championship leader was able to walk away from the wreckage but the session was red flagged for 15 minutes while the oil was removed from the track and the mangled car was craned away.

When practice finally resumed, Kubica moved up to fifth fastest but try as they might, none of the drivers could better Massa's final effort.

Further down the times David Coulthard took to the track for the first time since announcing his impending retirement.

The veteran Scottish Red Bull driver flirted with the grass more than once on his way to eventually ending ninth fastest.