Williams has launched its 2013 contender, the FW35, at the Circuit de Catalunya ahead of the second and penultimate pre-season test.

The car, which is the culmination of more than 12 months' research and development by the team's technical departments in Grove, features improvements in several key areas over last year's race-winning FW34.

"Given the rule stability over the winter, I'm pleased with the gains that we've been able to make with this car," said Technical Director Mike Coughlan. "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."

Despite being an evolution of the FW34, more than 80 per cent of the FW35 is new. It has a new gearbox, new rear suspension, new radiators, a new floor, new exhausts, new bodywork, a new nose and a significant amount of weight has been saved as well.

With many new parts on the car, the team has carried out a lot of reliability work over the winter. The gearbox alone has already completed 3200kms on the dyno, a lot of which was conducted in the form of five straight Grand Prix weekends.

The car will continue to be developed throughout the year, beginning with an aerodynamic upgrade in time for the first race. By season's end it is expected that the FW35 will have made strong performance improvements and Coughlan is in no doubt over the main area of gain.

"The Coanda effect is going to be a big thing for us," Coughlan says. "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."

"A group of talented people with good imagination and plenty of courage have been working together to build the FW35," said Frank Williams. "We will have to wait until Australia to truly see what we have, but we believe it is step forward from last year's car which was also a very competitive vehicle. Pastor is a delightful character who is a massively determined racer, whilst Valtteri is quieter but still waters run deep and he is a highly gifted driver.

"Williams has been at the top many times over the last 30 years. It's the nature of the sport to have ups and downs, but when we are down we always fight our way back. I'm hoping that with the current team we have in place, our new FW35, the combined talent of Pastor, Valtteri and Susie, and the continued support from our partners; we will be in a position to challenge the very best."