The car was first raced in the 1961 British Empire Trophy, where Rob Walker put Jack Fairman in the car, but the start was an inauspicious one as Fairman crashed on lap 2. In the British Grand Prix at Aintree, Fairman drove the car again, but surrendered it to Stirling Moss after his Walker-entered Lotus 18 failed. The car was disqualified for outside assistance on lap 56. The car's last major F1 race was its moment of motor racing immortality, as Moss drove the P99 to victory in a damp International Gold Cup at Oulton Park. In February 1963, the car, having been fitted with a 2.5-litre Climax engine, was driven by Graham Hill in the Australian Grand Prix at Warwick Farm and the Lakeside International at Lakeside, placing sixth and second respectively. The P99's final competition action during this period came in the British Hillclimb championship in 1964, 1965, and 1966, with Peter Westbury winning the title in 1964. The car has competed in recent years in historic races