Dozens of near-identical city cars are preparing to take on the ultimate challenge of a 24-hour race on the Silverstone Grand Prix circuit.
The Citroen C1s will line up at 17:40 BST on Saturday and the chequered flag will come down at the Northamptonshire venue on Sunday afternoon.
The event marks a return to the 'home of motorsport' after being staged in Anglesey last year.
One competitor described it as "the most bonkers race".
The first 24-hour endurance race for the small city car was staged by the C1 Racing Club in 2017.
Motorsport journalist Matt Prior took part in 2019 and said the contest was "24 hours of pure lunacy" and "the most bonkers race I've been in".
He reported that 13 of the 99 starters had rolled during the race and the lead driver, wrongly convinced he was on his last lap, was overtaken at the end by the car that started 99th.
The British Racing and Sports Car Club (BRSCC) partnered with the C1 Racing Club for the first time to stage the race in 2022.
The increasing cost of racing at Silverstone persuaded the C1 club to carry out a survey of its drivers, which led to a move to Anglesey for 2024.
A spokesperson for the BRSCC said: "From beginning the race late Saturday afternoon, racing through darkness overnight and back into the light of day, drivers and teams will face many challenges on and off track.
"Just making it to the chequered flag alone is a impressive feat, but to do well or even win this event it will require a perfectly executed mix of teamwork, strategy, preparation, consistency – and even a little luck."
