Watch Mercedes' new W09 being fired up for the first time

Mercedes are the defending champions in both drivers' and constructors' championships. Peter J Fox/Getty Images

Mercedes has released a video of its new W09 F1 car being fired up for the first time at its factory in Brackley.

The Formula One season is not due to get underway until the season-opener in Australia on March 25, but teams are working hard to meet build deadlines ahead of the first official pre-season test later this month. The fire-up is a milestone in each team's preparations for the start of the season and Mercedes released a short clip of the moment via its social media channels.

Speaking about progress with the W09 in an interview on the Mercedes website last week, team principal Toto Wolff said: "It's never going completely seamlessly or smoothly, because you are trying to push the boundaries, make the cars as light as possible and - eventually - as quick as possible. We have had a good winter, I would say. No real drama, but there is always stress within the organisation at this time of year."

Mercedes is due to launch its new car on February 22 at Silverstone when the W09 will also complete its first miles in a 100km shakedown/filming day. The car will then be transported to Barcelona for the first day of testing on February 26.