The session began in dry conditions, but leaden skies threatened to unload and there were spots of rain from the start. First victim was Johnny Cecotto Jr of Addax, who spun through 180-degrees at the Nordkurve on his first flying lap, and Arden's Simon Trummer almost followed suit seconds later.
Esteban Gutierrez of Lotus and Marcus Ericsson of iSport traded top spot early on, but it was points leader Luiz Razia (Arden) who hammered home the first truly representative P1 time, a 1m24.151s. That was demoted moments later by Valsecchi's 1m24.031s, 0.12 seconds faster.
Gutierrez was third fastest on 1m24.269s, just 0.02s quicker than Coloni's Stefano Coletti. Both Gutierrez and team-mate James Calado have a 10-place grid penalty hanging over them going into Friday afternoon's qualifying period for misdemeanours at Silverstone.
The session was interrupted by a sizeable accident sustained by Giancarlo Serenelli's Lazarus entry. He ran wide onto the damp Astroturf on the exit of the corner entering the stadium section and clipped the grass, which spun him across the track and into the tyre wall on the inside of the corner. He slammed into the wall, tearing the left-front wheel off as he spun around three times.
The Venezuelan was able to climb out of his car unaided, but was taken to the medical centre for a check-up. When the session was restarted, sufficient rain had fallen to render the remaining running time pretty useless.
Free Practice result
1. Davide Valsecchi DAMS 1:24.031 10
2. Luiz Razia Arden International 1:24.151 9
3. Esteban Gutiérrez Lotus GP 1:24.269 8
4. Stefano Coletti Scuderia Coloni 1:24.289 8
5. Giedo van der Garde Caterham Racing 1:24.337 9
6. Fabio Leimer Racing Engineering 1:24.342 8
7. James Calado Lotus GP 1:24.462 9
8. Max Chilton Carlin 1:24.573 8
9. Marcus Ericsson iSport International 1:24.622 9
10. Fabio Onidi Scuderia Coloni 1:24.688 10
11. Josef Kral Barwa Addax Team 1:24.804 9
12. Johnny Cecotto Barwa Addax Team 1:24.838 12
13. Tom Dillmann Rapax 1:24.888 9
14. Nigel Melker Ocean Racing Technology 1:24.924 9
15. Jolyon Palmer iSport International 1:24.965 9
16. Nathanaël Berthon Racing Engineering 1:24.974 9
17. Felipe Nasr DAMS 1:24.977 8
18. Rodolfo Gonzalez Caterham Racing 1:25.051 9
19 Rio Haryanto Carlin 1:25.108 10
20. Simon Trummer Arden International 1:25.557 9
21. Stéphane Richelmi Trident Racing 1:25.665 12
22. Victor Guerin Ocean Racing Technology 1:26.071 11
23. Sergio Canamasas Venezuela GP Lazarus 1:26.475 11
24. Julian Leal Trident Racing 1:26.762 11
25. Giancarlo Serenelli Venezuela GP Lazarus 1:27.459 7
26. Ricardo Teixeira Rapax 1:28.126 8