Alonso leads first day of Silverstone test amid bizarre incident

The red flag came midway through the afternoon, when a gust of wind blew a plank of wood off the start-light gantry hanging over the home straight.

Fortunately there were no cars in that area at the time, and the plank also dropped onto an area of the track that was off the racing line.

McLaren-Honda driver Alonso was one of two drivers to clock up over 100 laps, with his 1m31.290s best posted in the morning when the track was dry.

That was half-a-second quicker than his qualifying ahead at last weekend's British Grand Prix, thought it was set on super-soft tyres compared to the softs used at the GP.

Mercedes development driver Esteban Ocon finished second quickest, the 19-year-old Frenchman finishing 1.543s adrift with a time set on the medium tyre, before going on to complete 123 laps, the most of any driver.

Williams development driver Alex Lynn was third fastest, 1.6s slower than Ocon, closely followed by Ferrari junior Charles Leclerc and Force India's development driver Nikita Mazepin.

Leclerc completed just 18 laps for Ferrari, with only one of those coming in the afternoon.

Toro Rosso's Carlos Sainz Jr was sixth quickest of the 11 on track, ahead of American GP3 racer Santino Ferrucci, making his F1 test debut for Haas.

Pascal Wehrlein completed 48 laps testing compounds and structure concepts of Pirelli's 2017 tyres using a 2014 Mercedes, with the Manor driver classified eighth with a lap of 1m34.982s.

Manor's Rio Haryanto was ninth, followed by Renault test driver Sergey Sirotkin and Red Bull's Pierre Gasly, who finished the day bottom of the timesheet, 12.601s off the pace.

Gasly's first lap was his most interesting, as he conducted a trial of the halo cockpit protection device for Red Bull.

The 20-year-old Frenchman only managed seven laps in the morning as Red Bull was forced to replace some cabling inside the car, but managed another 40 in the afternoon.

The afternoon running was wet, ensuring the morning laptimes remained unbeaten.

DAY ONE TESTING TIMES