Williams have been forced to withdraw from the opening day of Formula One pre-season testing in Spain because their car is not ready.

The British team were due to be among the sport’s 10 outfits to hit the track at Barcelona’s Circuit De Catalunya on Monday for the first winter running.

But in a blow to the team, which last year finished last in the constructors’ championship, deputy team principal Claire Williams revealed they would only be watching from the sidelines.

“Unfortunately, we have had to delay the start of our pre-season Barcelona test to Tuesday morning.

“We have had an incredibly busy winter at Grove getting the FW42 prepared for the season ahead and, despite everyone’s best efforts, we need some more time before it will be ready to run.

“Our absolute priority is to always ensure we bring a car to the track that is the best that it can be and, sometimes, that takes longer than you’d anticipate or like. It’s clearly not ideal but, equally, it’s not the end of the world.

“We will obviously have our work cut out to recover the time lost but we still have seven days of testing left and we will be maximising that time to prepare the car for the first race.”

British rookie George Russell, celebrating his 21st birthday, and the returning Robert Kubica will be playing catch-up for a team bidding to bounce back from last season’s miserable campaign.

The first pre-season takes place over four days before a second four-day test the following week.

The 2019 Formula One season starts on March 17 in Melbourne.