2008 world champion Marco Simoncelli brought his 250GP career to a disappointing end with this crash from the lead during the season-ending Valencia Grand Prix (see below for full sequence).

The Metis Gilera rider began the race needing to overturn a 21-point lead to snatch the title from Hiroshi Aoyama, and looked on the brink of doing so when the Scot Honda star shot off track early in the race.

Simoncelli was leading at the time of Aoyama's trip through the gravel trap, but the Japanese regrouped and was soon comfortably ahead of the eleventh place he needed even if Simoncelli won.

Then, on lap 21, Simoncelli lost the front of his machine at turn two and crashed out - instantly handing Aoyama the last 250cc crown and costing Simoncelli second in the standings to Hector Barbera.

Simoncelli won six races compared with four for Aoyama - but whereas Aoyama scored points in every race, Simoncelli suffered five non-scores.

Both riders, although with Barbera and Alvaro Bautista, will move to MotoGP next year.