Torrential rain battered the historic Monza circuit to virtually wash out first practice for Sunday's Italian Grand Prix.

As thunder and lightning boomed and crackled overhead, the drivers and pit crews, as well as fans and photographers, were forced to take shelter.

The rain was so heavy towards the end of the 90-minute session, the water began to bubble up through the drains directly in front of the teams' garages.

That led to several mechanics taking on a different role as they grabbed brooms to sweep away the deluge that threatened to flood the garage floors.

With five minutes remaining, and with the rain showing no sign of relenting, race control eventually red-flagged the session.

Not that a driver would have ventured out in such conditions in any case given the obvious dangers.

Come the conclusion, there was the unusual sight of a Force India at the top of the timesheets, with Adrian Sutil's lap of one minute 32.842 seconds.