Changeable weather conditions, together with the late arrival of a supply of the latest Mercedes engines, has caused McLaren to cancel today's test programme at Silverstone.

The Woking team had been hoping to run GP2 champion Lewis Hamilton, who in fact completed a couple of shakedown laps, however, rather than 'waste' one of its few (five) remaining test days before the end of the season, has opted to postpone its programme until tomorrow.

It's business as usual for the remaining teams however, with all the Bridgestone teams, bar Ferrari, on duty, along with Renault.

Spyker, sporting a new orange livery (pictured), but the front wing still in the old MF1 colours, is running Adrian Valles, with Ernersto Viso scheduled to take over tomorrow.

Heikki Kovalainen and Nelson Piquet Jr are on duty for Renault, with Toyota represented by Ricardo Zonta and Franck Montagny. WilliamsF1 has Narain Karthikeyan on duty, whilst Sakon Yamamoto is driving the Super Aguri.