A major shake-up of technical staff, plus new driver Bruno Senna, left, has accompanied the launch of the new car as Williams attempt to refocus for the new season [GETTY]

Former world champions Williams presented their new car on Tuesday and declared a fresh start after enduring their worst season in Formula One.
 
A Renault engine has taken the place of last year's Cosworth, Brazilian Bruno Senna has ousted veteran compatriot Rubens Barrichello and a new technical line-up is in charge following the departures of Sam Michael and Patrick Head.

The dark-blue-and-white FW34 that was rolled out of the garage without fanfare on a chilly morning before the first pre-season test was without doubt the least attractive Williams since the 'Walrus-nosed' FW26 of 2004.

It featured the by-now conventional stepped nose that has appeared on all the 2012 cars with the exception of McLaren.

Williams, who scored just five points last year with Barrichello and Venezuelan Pastor Maldonado, will not care how it looks so long as it is quicker and more reliable than its predecessor.

All change

"One could say that looking at the Williams F1 Team today we are off to a truly fresh start," said team founder Frank Williams in a statement.

"We have a new car, new driver line up, new engine and new senior personnel. We also have a number of new partners who have joined the team in the past few months.

"The team has had a good winter at the factory and we feel ready and strong for the fight."

While the Renault engine is the same as that used by champions Red Bull, it is also identical to the one powering Caterham, the former Team Lotus who have yet to score a point.

The roll-out was a novelty for Senna, who scored two points and started the final eight races of 2011 with Renault. He made his F1 debut in 2010 with struggling HRT, who did not have a car ready to test that year.

"This is my ever first pre-season testing programme since I started in Formula One two years ago," said the Brazilian.

"I'm really motivated and looking forward to working hard and with everyone in the team. I hope we have a successful month testing and developing the car so we arrive in Melbourne as well prepared as possible."

Melbourne hosts the opening grand prix of the season on March 18.