Toyota's Jarno Trulli led the way this morning in the opening practice for Sunday's Belgian Grand Prix - although running was severely disrupted by rain, making the times pretty meaningless.

Indeed of the twenty drivers only half of them posted a time in the dry - and unsurprisingly they consequently locked out the top-ten.

Precipitation hit the 7 kilometre Spa-Francorchamps circuit around 30 minutes into the 90 minute session, and Trulli was top prior to the heavens opening on a 1 minute 49.675 seconds.

Current F1 championship leader Jenson Button was second for Brawn GP, on a 1m 50.283s, closely followed by double world champion, Fernando Alonso and then rookies Sebastien Buemi and Jaime Alguersuari.

Buemi was one of the few drivers to have a noticeable off, when he spun off at the exit of Puohon and damaged the front wing on his Toro Rosso.

For a long time Buemi and his STR team-mate Alguersuari, as well as Ferrari stand-in Luca Badoer were the only runners to venture out and set times in the wet.

As the clock ticked on though more went out including Heikki Kovalainen. Like Buemi the Finn also suffered an off. In contrast though, he was lucky as he just avoided contact with the barriers and could continue on in his McLaren-Mercedes MP4-24.

Of those runners who failed to set a time in the dry, Giancarlo Fisichella was best on a 2 minute 03.972 seconds, and eleventh overall on the timesheets, with Nico Rosberg around five tenths slower in his Williams and twelfth.

McLaren's Lewis Hamilton and Red Bull Racing's Sebastian Vettel both failed to set a time, the latter having been forced into 'conservation mode' as he has already used up four of his eight allowed engines this year and of those left only two are brand new.

To see the full free practice 1 times from Spa click here.