Australia's Casey Stoner continued his excellent recent form with the quickest time in practice for Sunday's British MotoGP at Silverstone.
Stoner topped the timesheets on Friday the morning before producing another stunning lap to lead in the afternoon's rain-hit second session.
His last lap gave him a 0.797 second lead over Marco Simoncelli, with Nicky Hayden third fastest.
It was an excellent day for Britain's Cal Crutchlow, who finished fourth.
Repsol Honda rider Stoner said: "I'm quite happy with that, it was a tough day with the weather but at least we have experience in the wet and the dry.
"The bike felt pretty good but we struggled with the tyres at times as the temperature was so low. But that is racing in England for you and we have to get on with it.
"I know I could take the championship lead this weekend but it is not the end of the world if I don't. I am enjoying my racing at the moment and the championship is a long way off being decided yet."
A brief shower had ended by the time the second session began but the riders were faced with a track which was still very wet in places.
Yamaha's Crutchlow excited the home crowd by setting the early pace but Stoner soon had his bike back at the top of the standings.
The times came down as the track dried out, with Gresini Honda's Simoncelli finding top spot with 20 minutes remaining as he broke the two minutes 20 second barrier.
The track was growing quicker by the minute and Stoner and reigning champion Jorge Lorenzo continued to trade faster laps in the final 10 minutes.
However, there was still time for change as the sun finally appeared and Ducati rider Hayden shot into the top three.
But Stoner, winner of three of the five races this year, timed his best lap to perfection, leapfrogging into first place with a final circuit of two minutes 15.666 seconds.
The drying track presented the field with problems and Crutchlow - whose best qualifying performance to date is sixth - feels there is more to come from him.
He said: "Half the track was completely dry, and the other half was very wet which is the worst conditions you can have. It was very dangerous.
"You get a lot of heat into the tyres over the dry section and then chuck it into a wet corner and there is no grip at all.
"So to be running in the top six against the best riders in the world is not bad going and it bodes well for if we have a wet race. I could have gone faster as well.
"The wet weather is always a leveller as everyone is in the same boat but we all want a dry race."
Seven-time champion Valentino Rossi was the only rider new to Silverstone and it showed. The Italian Ducati rider was 3.769 seconds slower than Stonor and he finished the afternoon in ninth place.
Yamaha's Colin Edwards - racing just a week after fracturing his collarbone - looked far from fully fit and limped around to finish in last.
In the Moto2 class British riders Scott Redding and Bradley Smith put in good displays.
Redding, 18, put in the fastest lap of the day as he topped the morning session while 20-year-old Smith ended the second session in third.
British MotoGP practice times:
1 C Stoner (Aus) Repsol Honda 2'15.666
2 M Simoncelli (It) Gresini Honda 2'16.463
3 N Hayden (USA) Ducati 2'17.070
4 C Crutchlow (GB) Tech 3 Yamaha 2'18.109
5 J Lorenzo (Sp) Yamaha 2'18.683
6 A Dovizioso (It) Repsol Honda 2'18.783
7 B Spies (USA) Yamaha 2'18.820
8 K Abraham (Cze) Ducati 2'19.009
9 V Rossi (It) Ducati 2'19.435
10 T Elias (Sp) LCR Honda 2'19.612
11 A Bautista (Sp) Suzuki 2'20.337
12 L Capirossi (It) Pramac Ducati 2'20.607
13 H Barbera (Sp) Aspar Ducati 2'20.639
14 R De Puniet (Fr) Pramac Ducati 2'20.982
15 H Aoyama (Jpn) Gresini Honda 2'21.026
16 C Edwards (USA) Tech 3 Yamaha 2'24.724