He was the second of three sons of Charles Thomas Brock Sangster, an engineer and the owner of Cycle Components Ltd, which became known as the motorcycle brand Ariel in 1902.

It was interrupted by the First World War, in which Sangster served with the City of Birmingham battalion of the 14th Royal Warwickshire Regiment.

[2] In 1918 Sangster joined the Cycle Components Manufacturing Company, where his father was managing director.

Sangster developed a motorcycle with a 4 hp White and Poppe engine which proved extremely successful.

He appointed Turner as Chief Executive of the Automotive Division (comprising BSA, Ariel, Triumph, Daimler, and Carbodies, makers of London taxicabs).