Valtteri Bottas topped the times for Alfa Romeo ahead of home hero Lewis Hamilton of Mercedes in Friday's rain-swept opening practice session at the British Grand Prix.
The Finn, who was Hamilton's Mercedes team-mate before moving teams this year, clocked a best lap time of one minute and 42.249 seconds in a relatively dull session with limited serious running for fast lap times.
Seven-time world champion Hamilton, the subject of offensive racist and homophobic comments by Nelson Piquet reported this week, was half a second adrift of Bottas, but ahead of Carlos Sainz, his Ferrari team-mate Charles Leclerc and Mick Schumacher of Haas.
There was little meaningful action and few incidents, but the session ended with a red flag when the under-pressure Lance Stroll spun into a gravel trap at Copse in his Aston Martin.