This brooch commemorates the breaking of the World Land Speed Record by the yachtsman, hydroplane champion, aviator and racing car driver Captain George Eyston (1897-1979). Eyston broke the land speed record in 1937 in 'Thunderbolt', a car which he designed, built and drove, racing at 312.203 miles per hour on the Bonneville Salt Flats in Utah. He went on to break the record twice more in 1938. His successful attempts attracted a great deal of publicity and was commemorated in souvenir items such as tobacco cards. Time magazine described Eyston in his 1938 attempt as driving 'over the measured mile of glistening salt at an average speed of 345 m.p.h., faster than man had ever travelled on earth.'

The car was powered by two Rolls Royce aero engines and, according to Eyston's daughter Mrs Elwes, it was Rolls Royce who presented her mother with this brooch, just as it had earlier presented Lady Campbell with one following Sir Malcolm Campbell's successful attempts. The brooch depicts 'Thunderbolt' with a high tail fin which appears to correspond to its design in 1937.

The design is made up of a dense concentration of diamonds in a discreet platinum setting, using the strength and versatility of platinum to create a streamlined jewel evoking the speed and modernity of 'Thunderbolt'.