Williams has taken the covers off its 2009 Formula One challenger, the FW31, at the Portimao circuit.

The car, revealed in an interim testing livery, will make its on-track debut at the Portuguese circuit later today with test driver Nico Hulkenberg at the wheel.

Williams finished eighth in the constructors' championship in 2008 but has focused its attention on the new season for some time and will hope that Nico Rosberg and Kazuki Nakajima will be able to reap the benefits when the new season kicks off in Australia.

To view images of the new car, CLICK HERE.