To assist the low profile and low frontal area, the driver reclined sharply behind the wheel (an idea seen in the 18, and pioneered over a decade previously by Gustav Baumm at NSU[5]), leading to the nickname 'The Bathtub', while front coil/damper units were moved inboard (as in the 1948 Maserati).

When it first appeared at the Dutch Grand Prix, the futuristic 25 was inspected by John Cooper, who asked Chapman where he had put the frame tubes in the car.

Clark gained his revenge the following year, taking his first World Championship in the 25, by winning 7 races, Belgium, France, Holland, Britain, Italy, South Africa, and Mexico.

Following the United States GP, a 25 was taken to the Indianapolis Motor Speedway for evaluation, where they also trialled Lucas electronic ignition for Ford.

At the final race in Mexico, just as in 1962, the Climax engine developed an oil leak and with literally a lap to run Clark coasted to a halt in sight of world championship victory, this time conceding to John Surtees.

Despite the introduction of the Lotus 33 in 1964, the 25 was still used until well into the 1965 season, Clark taking the car's final win at the 1965 French Grand Prix.