After two dry days, rain has arrived at Donington Park in time for race day - helping Ducati's Troy Bayliss to dominate this morning's 20-minute warm-up.

Although there was virtually no standing water, the resurfaced circuit is rumoured to offer little grip when wet, forcing many teams to experiment frantically to find a suitable set-up.

With lap times around 15secs from full dry pace, the balance between man and machine has also swung towards the former - allowing the likes of Aprilia's Shane Byrne and D'Antin Ducati's Ruben Xaus to feature at the front, alongside established wet weather riders Bayliss and Sete Gibernau.

Bayliss led most of the session and will head into this afternoon's race having held a frightening 1.5secs advantage over Gibernau, each having saved some lurid slides along the way.

Honda riders Nicky Hayden and Colin Edwards claimed a promising third and fourth, but almost 2secs from Troy, while Carlos Checa was the top Yamaha in fifth.

Second fastest Ducati was the year old machine of Ruben Xaus, who finished a tenth of a second clear of the second factory Desmosedici of Loris Capirossi. Suzuki's Kenny Roberts claimed a late eighth (as top Bridgestone rider).

Top Brit was Byrne, despite slipping to ninth after 'problems' in the final five minutes - when he was comfortably inside the top four.

Pole sitter Valentino Rossi was a cautious eleventh, 3.5secs from Bayliss, while title rival max Biaggi was just 20th. Injured Italian Marco Melandri didn't risk riding this morning and remains doubtful for the race.

But what will the unpredictable British weather do in the five hours between now and the 15.30 (local time) race start...?

Warm-up:

1. Bayliss
2. Gibernau +1.5secs
3. Hayden +1.8secs
4. Edwards +1.9secs
5. Checa +2.0secs
6. Xaus +2.7secs
7. Capirossi +2.8secs
8. Kenny Roberts +2.88secs
9. Byrne +3.0secs
10. Barros +3.2secs
11. Rossi +3.5secs
12. Hopkins +3.6secs
13. McWilliams +3.66secs
14. Kurtis Roberts +4.1secs
15. Fabrizio +4.7secs
16. Tamada +4.9secs
17. Nakano +5.2secs
18. Hodgson +6.1secs
19. Aoki +6.3secs
20. Biaggi +6.6secs
21. Burns +7.2secs
22. Abe +8.0secs
23. Hofmann +10.1secs