Fernando Alonso clocked the fastest time in the opening day of a rain-affected Formula 1 in-season test at Silverstone.
The McLaren driver chalked up 105 laps at the Northamptonshire circuit with his personal best arriving in dry conditions before heavy rain hit in the afternoon.
Alonso was more than 1.5s faster than his nearest rival Esteban Ocon, who piloted the world championship leading Mercedes.
The session was red flagged following a strange incident that saw a gust of wind blow a piece of wood from the startline gantry onto the track.
Luckily the debris fell off while the section of the track was empty.
It proved to be a productive day for McLaren as they continued to develop new aero components, while completing additional testing of its upgraded Honda engine.
McLaren and Mercedes were the only teams to notch up more than 100 laps during the day.
Williams emerged third fastest courtesy of development driver Alex Lynn with the Brit a further 1.5s adrift.
Charles Leclerc completed just 19 laps for Ferrari after being hampered by a power unit issue in the afternoon.
The GP3 star ended the day fourth quickest ahead of Force India's Nikita Mazepin, Toro Rosso's Carlos Sainz and F1 debutant Santino Ferrucci, driving for Haas F1.
Pascal Wehrlein jumped behind the wheel of a 2014 specification Mercedes to conduct development on Pirelli's 2017 specification tyre structures.
Meanwhile, Rio Haryanto and Sergey Sirotkin posted more than 100 laps between them driving for Manor and Renault respectively.
Pierre Gasly (Red Bull) propped up the times on a day that saw the Milton Keynes operation trial the new Halo head protection system for the first time.
Result: Formula 1 Silverstone Test Day 1
Position | Driver | Car | Time | Gap | Laps |
---|---|---|---|---|---|
1 | Fernando Alonso | McLaren/Honda | 1:31.290s | – | 105 |
2 | Esteban Ocon | Mercedes | 1:32.833s | +1.543s | 123 |
3 | Alex Lynn | Williams/Mercedes | 1:34.433s | +3.143s | 54 |
4 | Charles Leclerc | Ferrari | 1:34.446s | +3.156s | 19 |
5 | Nikita Mazepin | Force India/Mercedes | 1:34.521s | +3.231s | 35 |
6 | Carlos Sainz | Toro Rosso/Ferrari | 1:34.643s | +3.353s | 91 |
7 | Santino Ferrucci | Haas/Ferrari | 1:34.866s | +3.576s | 55 |
8 | Pascal Wehrlein | Mercedes | 1:34.982s | +3.692s | 48 |
9 | Rio Haryanto | Manor/Mercedes | 1:35.631s | +4.341s | 64 |
10 | Sergey Sirotkin | Renault | 1:36.575s | +5.285s | 48 |
11 | Pierre Gasly | Red Bull/Renault | 1:43.891s | +12.601s | 52 |