Esteban Ocon set the pace on the second morning of the Silverstone in-season test as he led Kimi Raikkonen by 1.5s.
The Mercedes youngster posted a 1:31.212 on the soft compound tyre in the final half hour of the session to top the times, with his lap also the quickest of the test so far. Ocon beat Fernando Alonso's time from Tuesday by just 0.078s, although the Frenchman was only using the soft compound tyre compared to the supersoft run by McLaren.
Raikkonen was second for Ferrari on the medium tyre as Ferrari enjoyed a more productive session before the lunch break than it had on Tuesday. A power unit problem limited Charles Leclerc's mileage but Raikkonen managed 35 laps with a best time of 1:32.730.
Red Bull also remained on the medium tyre throughout the first three and half hours, with a late lap from Pierre Gasly good enough for third in the standings. Gasly Completed 42 laps on Wednesday having also been hampered by reliability problems on the opening day.
Fourth quickest was Jolyon Palmer for Renault, as the British driver set a 1:33.470 on the soft tyre 90 minutes into the session. While the majority of drivers improved late on, Palmer didn't better his time despite a late run on softs following a number of high fuel stints on the hard compound.
Stoffel Vandoorne took over the McLaren from Alonso for the second day but didn't register a lap time for more than an hour and a half. Some late laps on the soft tyre saw him set the fifth quickest time - just 0.003s slower than Palmer - but he didn't get to test the faster supersoft as the Spaniard had.
Haas carried out plenty of pit stop practice at the start of the day, with Santino Ferrucci not being allowed to complete a timed lap as the team worked on an area it had been unable to address during pre-season. The practice also followed a slow stop for Esteban Gutierrez during Sunday's British Grand Prix. Ferrucci was later sent out on soft tyres to push the car further - admitting he had a lot of time still to find in the high-speed corners at Silverstone - and he posted a 1:33.934 in the final five minutes.
Toro Rosso debutant Sergio Sette Camara enjoyed a largely productive morning in the car, but did suffer one major moment on the pit straight. The Brazilian lost control exiting the final corner and had a half spin at high speed, collecting the car and continuing without damage.
Pirelli made the most of the dry weather throughout the morning to complete the most mileage with Pascal Wehrlein in the 2014 Mercedes, while Jordan King was bottom of the timing screens having managed just 24 laps for Manor and only used the medium tyre.