Williams has brought F1's launch season to a close after revealing the new FW35 in Barcelona prior to the start of the second pre-season test of the year at Catalunya.

The team elected to delay the debut of the new car in order to carry out further development work on a number of parts at Jerez, where it ran the FW34 complete in the livery that will be seen this season.

The FW35 is an evolution of the car that saw Williams return to the top step of the podium last year, but is more than 80 per cent new as the Grove based team seeks to perform on a more consistent basis in 2013 - having only finished eighth in the standings last year despite Pastor Maldonado's Spanish Grand Prix success.

A new gearbox, new rear suspension, new radiators, a new floor, new exhausts, new bodywork and a new nose all feature, whil the team has managed to save what it referred to as 'a significant amount of weight' compared to the car it replaces.

"Given the rule stability over the winter, I'm pleased with the gains that we've been able to make with this car," technical director Mike Coughlan said. "It's a better, more refined Formula One car than the FW34 and I think everyone involved in the project can feel proud of the work they've done.

"The Coanda effect is going to be a big thing for us. There's been no rule clarification concerning this area of the car, so we'll work closely with Renault to maximise the available gains. Use of the DRS is more restricted this year, so we'll take some resource away from that and focus on other areas."

Maldonado remains to lead the team for another season with Valtteri Bottas stepping up from the role of test and reserve driver to partner the Venezuelan.