By the mid-1920s the land speed record had become a point of national prestige contested primarily by British and American teams. Louis Coatalen's Automobiles Talbot-Darracq organisation was financially constrained and unable to fund substantial new development, so the design team sought a way to build a record car from available hardware. The solution was to press two Sunbeam Matabele aircraft engines — surplus 22.4-litre aero units previously used in a powerboat — into service as a paired power source.
Although the car carried the "1000 HP" designation as a marketing identity, its actual combined output was closer to 900 hp (670 kW). The car was designed by Captain Jack Irving, who incorporated all-enveloping streamlined bodywork — an aerodynamically considered feature that was advanced for the period — and arranged the two engines in an unusual tandem layout, with one mounted ahead of the driver and one behind.
Starting the pair of engines required a specific procedure: compressed air initiated the rear engine first, then the front engine was engaged through a mechanical friction clutch. Once the two units were synchronised in speed, they were locked together via a dog clutch for the record run. Final drive to the rear axle was accomplished through a pair of chains — a primitive feature acknowledged even by contemporaries, and one that carried additional psychological weight at the time of the car's construction.
Only weeks before the record attempt, the racing community had been shaken by the death of J. G. Parry-Thomas, who was killed when a drive chain in his record car Babs broke at speed. Initial reports suggested he had been decapitated by the chain, though later investigation of the recovered wreckage pointed instead to failure of the rear right-hand wheel causing the car to overturn. The Sunbeam's chains were enclosed within an armoured steel housing, a design element present from the car's original specification rather than added in response to the Parry-Thomas accident.
The tyres were specially manufactured to withstand sustained speeds above 200 mph, though they were rated for only three-and-a-half minutes at such velocities.
The Sunbeam 1000 HP was the first non-American car to be run on Daytona Beach for a land speed record attempt, a detail that underscored the symbolic significance of the venue for such efforts at the time. On 29 March 1927, Henry Segrave drove the car across the measured mile and set a new land speed record of 203.79 mph (327.97 km/h) — the first officially ratified two-way average above 200 mph.
The achievement made Segrave a national figure in Britain and cemented Sunbeam's reputation as the leading manufacturer of record-breaking machinery. It came at a moment when American-built cars had dominated land speed record attempts, making the success of a British car on American soil particularly resonant.
The car's last significant run was a demonstration circuit at Brooklands, conducted at low speed on a single engine. It was not campaigned further for competitive record attempts. The Silver Bullet, Sunbeam's next purpose-built land speed record car, was constructed in 1929 for Kaye Don, but despite its impressive appearance and twin 24-litre supercharged engines, it failed to achieve any records and represented the company's final effort in the discipline.
The Sunbeam 1000 HP Mystery passed into preservation and is today a centrepiece exhibit at the National Motor Museum in Beaulieu, Hampshire, where it is displayed alongside other significant vehicles from British motorsport and automotive history.
The Sunbeam 1000 HP Mystery holds a firm place in the canon of land speed record history as the machine that first demonstrated that 200 mph was achievable by an automobile. Its twin-aero-engine configuration, while technically inelegant, solved the power problem within the financial and material constraints facing the Talbot-Darracq team and produced a result that stood as a benchmark in automotive achievement. Henry Segrave's drive at Daytona in 1927 is consistently cited among the defining moments of the interwar record-breaking era, alongside his subsequent exploits in other cars.