Julian Simon has doubled his 2009 125cc World Championship lead to 50 points with his third victory of the season in a frenzied five-lap 125cc British Grand Prix at Donington Park.

After a wet warm-up the original race began in cool, windy and (officially) dry conditions. But the weather gradually deteriorated and when the race was stopped due to rain on lap 15 of 25, Pol Espargaro was leading by 3.296sec from Nicolas Terol, followed closely by Marc Marquez, Bradley Smith and Aspar Aprilia team-mate Simon.

Espargaro had fallen from the lead moments before the race was stopped, but with the starting order for the restart (the first race did not count in any other way) taken from the end of the last full lap the Derbi rider was able to assume 'pole position' for the five lap sprint.

Tyres of choice were full wets, soon justified by increasing rain, and the race began with Smith pulling a brave outside move to lead on the exit of turn one.

But the Englishman's hopes of winning the last Donington 125 grand prix for the foreseeable future came to an end when he crashed out at Coppice (the corner where Noriyuki Haga was injured in WSBK earlier this year) later in the lap.

Marquez inherited the lead and looked on target for his first ever grand prix victory, but he too fell - highsiding from his KTM at the Foggy Esses on the penultimate lap.

That mistake meant that the battling trio of Simone Corsi, Simon and 2008 home winner Scott Redding were now fighting for victory, with Simon making his winning pass on Corsi heading into McLeans on the last lap.

The Spaniard won by 0.390sec over the Italian, with Redding pulling a huge wheelie as he celebrated the second podium of his grand prix career and first since last year's shock victory.

Simon began round nine 25 points ahead of team-mate Sergio Gadea, who crashed out in the first race start. With third in the championship Smith, the first British rider to start his home GP on pole since Barry Sheene in 1977, finishing outside the points in 20th Simon couldn't have hoped for a better day.

Espargaro meanwhile didn't match his damp pace in the wet and finished tenth.

The mid-season summer break now takes place before the next round at Brno on August 16.

Race results - Donington Park:

1. Simon (Aprilia) 5 laps
2. Corsi (Aprilia) +0.390sec
3. Redding (Aprilia) +3.072sec
4. Terol (Aprilia) +6.209sec
5. Nakagami (Aprilia) +9.509sec
6. Salom (Aprilia) +11.211sec
7. Zanetti (Aprilia) +11.572sec
8. Aegerter (Derbi) +13.703sec
9. Vazquez (Derbi) +14.101sec
10. Espargaro (Derbi) +15.422sec

13. Glossop (Honda) +27.916sec
16. Jordan (Honda) +28.999sec
20. Smith (Aprilia) +38.938sec

DNF Lodge (Honda)
DNF Hastings (Honda)
DNF Webb (Aprilia)