Updated: Adds details on second session

Lewis Hamilton's Japanese Grand Prix weekend got off to the worst possible start today as the McLaren driver crashed out of the opening practice session at Suzuka.

The Briton is bidding to re-ignite his championship bid after back-to-back retirements in Italy and Singapore but an apparent error on his 10th lap saw him lose half of the opening 90-minute session, costing him valuable set-up time.

Entering the second part of the Degner Curve, Hamilton ran wide on the kerb before taking to the gravel and crunching heavily into the tyre barrier, removing his left-front wheel.

Hamilton, who trails championship leader Mark Webber by 20 points with four races remaining, was quickly out of the car and cut a forlorn figure as he waited in the underpass on the exit of the corner for the trackside marshals to clear away the stricken MP4-25.

With just two minutes left in the session, Hamilton's team-mate Jenson Button also had a lurid moment through Degner, his car pitching up wildly off the kerb and sliding towards the scene of Hamilton's accident.

Fortunately for Button, who ended the session down in 12th place, he stopped short of the barriers and was able to get his car back to the garage, where the McLaren team will no doubt be working to improve the balance of their cars ahead of second practice later today.

Hamilton had just set the fastest first sector time of the session at the time of his accident, and was running second to Red Bull's Sebastian Vettel, who won this race last year and set an ominous pace once again today and topped first free practice with team-mate Mark Webber second. Renaul'ts Robert Kubica and Force India's Adrian Sutil were third and fourth with Hamilton fifth.

Fernando Alonso was 13th.

Mechanics were able to repair Hamilton's car just in time to enable him to drive in the dying minutes of the second practice session.

However Vettel and Webber maintained their solid lead, with the Ferraris of Alonso and Massa in fourth and fifth behind Kubica in third. McLaren's Jenson Button was sixth

Rain is expected for the qualifying session early tomorrow morning.