Kimi Raikkonen led a Ferrari one-two in the Friday afternoon practice session at Silverstone.
The Toyotas showed good speed to take third and fifth with Ralf Schumacher and Jarno Trulli, while the McLarens could only manage fourth and sixth, with Lewis Hamilton ahead.
The majority of the action took place in a busy opening half-hour. The McLarens were briefly fastest, before the Ferrari drivers both took a turn on top.
All four title contenders were then momentarily shaded by Trulli, before Felipe Massa and Raikkonen restored Ferrari's advantage.
Raikkonen's 1:20.639 put him 0.650 seconds clear of his teammate, and although Massa twice improved his time on subsequent runs, he remained half a second adrift.
The McLarens were then shuffled down to the foot of the top ten as the Toyotas, Renault's Giancarlo Fisichella and the Williams all improved.
A brief rain shower in the first part of the lap limited opportunities for gains during the next 20 minutes, but even once the conditions cleared the McLarens were unable to get back on terms with the Ferraris.
Hamilton improved to fourth, equalling the time set by third-placed Schumacher's Toyota, but 0.742 seconds slower than Raikkonen. Fernando Alonso ended the session sixth, behind Schumacher's teammate Trulli.
Williams continued their strong morning form with Nico Rosberg and Alex Wurz taking seventh and eighth, followed by Mark Webber and Anthony Davidson.
Christian Klien made his first appearance in an official session since losing his Red Bull drive last September. He deputised for Jenson Button at Honda after the Briton suffered back pain in this morning's practice, and set the 18th fastest time.
Both Renaults had minor trips off the road during the afternoon, with Heikki Kovalainen going through the gravel at Brooklands, and Fisichella exploring the Copse run-off area. Honda's Rubens Barrichello also visited the gravel at the complex.
The only driver to damage his car was Adrian Sutil, who spun his Spyker in the middle of Copse and nudged into the wall on the outside of the corner.
Pos Driver Team Time Laps 1. Raikkonen Ferrari (B) 1:20.639 35 2. Massa Ferrari (B) 1:21.138 + 0.499 30 3. R.Schumacher Toyota (B) 1:21.381 + 0.742 34 4. Hamilton McLaren-Mercedes (B) 1:21.381 + 0.742 39 5. Trulli Toyota (B) 1:21.467 + 0.828 35 6. Alonso McLaren-Mercedes (B) 1:21.616 + 0.977 35 7. Rosberg Williams-Toyota (B) 1:21.619 + 0.980 40 8. Wurz Williams-Toyota (B) 1:21.650 + 1.011 37 9. Webber Red Bull-Renault (B) 1:22.137 + 1.498 31 10. Davidson Super Aguri-Honda (B) 1:22.143 + 1.504 40 11. Kovalainen Renault (B) 1:22.189 + 1.550 42 12. Fisichella Renault (B) 1:22.257 + 1.618 39 13. Kubica BMW Sauber (B) 1:22.372 + 1.733 41 14. Coulthard Red Bull-Renault (B) 1:22.428 + 1.789 23 15. Heidfeld BMW Sauber (B) 1:22.486 + 1.847 34 16. Sato Super Aguri-Honda (B) 1:22.487 + 1.848 38 17. Barrichello Honda (B) 1:22.511 + 1.872 39 18. Klien Honda (B) 1:22.833 + 2.194 45 19. Speed Toro Rosso-Ferrari (B) 1:22.840 + 2.201 42 20. Liuzzi Toro Rosso-Ferrari (B) 1:23.105 + 2.466 35 21. Albers Spyker-Ferrari (B) 1:23.113 + 2.474 35 22. Sutil Spyker-Ferrari (B) 1:23.720 + 3.081 30