London - Andrea Dovizioso set the pace in free practice ahead of the British Moto GP as the Ducati rider clocked the fastest overall time at 2:01.385 on Friday.
Dovizioso, who won the title at Silverstone last year, was followed in second place by Britain's Cal Crutchlow, who on Thursday extended his deal with LCR Honda until 2020.
Crutchlow finished just 0.005sec off the Italian, while Maverick Vinales of Yamaha had a strong day as he got within 0.061 of Dovizioso in third.
The threat of rain was in the air but it held off as the premier class got an important dry practice under their belts on a newly-surfaced Silverstone track.
Behind the front three was championship leader Marc Marquez (Honda) as the Spaniard ended the opening day 0.144 from the top.
Rounding out the top five was Austrian GP winner Jorge Lorenzo (Ducati), squeezing into an automatic Q2 spot on his final lap, while Australia's Jack Miller ended sixth fastest overall.
Marquez will be chasing a third win in his last five events in Sunday's race following his victories in the Netherlands and Germany.
Leading practice times on Friday:
1. Andrea Dovizioso (ITA/Ducati) 2:01.385s, 2. Cal Crutchlow (GBR/LCR Honda) at 0.005sec, 3. Maverick Vinales (ESP/Movistar Yamaha) at 0.061, 4. Marc Marquez (ESP/Repsol Honda) at 0.144, 5. Jorge Lorenzo (ESP/Ducati) at 0.397, 6. Jack Miller (AUS/Pramac Ducati at 0.434, 7. Johann Zarco (FRA/Monster Yamaha) at 0.577, 8. Valentino Rossi (ITA/Movistar Yamaha) at 0.767, 9. Andrea Iannone (ITA/Suzuki Ecstar) at 0.846, 10. Alvaro Bautista (ESP/Angel Nieto) at 1.063