Lewis Hamilton crashed his Mercedes formula one car today on his first day of pre-season testing.

The Briton's car careered in a straight line across the gravel runoff at the Jerez circuit and nose first into the tyre wall at turn six, the Dry Sack corner.

The car was slowed by the gravel but the wheel tracks indicated Hamilton had been a mere passenger with no response from the steering as it went off the track.

The team said he had a rear brake problem.

The 28-year-old up to that time was second fastest with a best lap of one minute 19.519 seconds when he brought out the red flags, stepped out apparently unhurt.

Germany's Nico Rosberg completed only 14 laps yesterday, the start of the test, after problems with the car's wiring loom left him stranded on the track with flames flaring briefly around the rear of the vehicle.