The Birmingham Small Arms Company (BSA) was founded in 1861 in Birmingham, England, to supply arms during the Crimean War. In the 1880s the company began to manufacture bicycles and in 1903 the company's first motorcycle was constructed. .
By 1909 they were offering a range of motorcycles for sale. 499cc side-valves Model H and Model K were their pre-war singles. Production ceased during WW1 while they pursued their traditional manufacturing, making guns, but returned quickly after the war, making their first V-twins in 1919. They made their first and only two-stroke, a 175cc unit construction bike, for only one season, in 1928. BSA's famous Star series started in the 1930s with the Blue Star singles in 250, 350 and 500cc versions. The Empire Stars followed. Val Page, formerly of Ariel, then Triumph, joined BSA to make their M-range in the late 1930s.
By World War II, BSA had sixty-seven factories and was well positioned to benefit from the demand for guns and ammunition. During the war it built 126,000 M20 motorcycles.
Post-war, the BSA Group bought Triumph in 1951. They also took over Sunbeam from AMC in 1936 (1943?) and Ariel in 1944. BSA also acquired New Hudson....making them the largest producer of motorcycles in the world. The Group continued to expand and acquire throughout the 1950s but by 1965 competition from Japan and Germany was eroding BSA's market share. By 1972 BSA was so moribund that it was absorbed into Manganese Bronze in a rescue plan initiated by the Department of Industry and many of the acquisitions were separated or sold. The motorcycle business was hard hit - plans to rescue and combine Norton, BSA and Triumph failed in the face of worker resistance and Norton's and BSA's factories were shut-down, while Triumph staggered on to fail four years later. Only the limited NVT Motorcycles survived. Enjoying the rights to the BSA marque, it was bought-out by the management and renamed the BSA Company. The UK rights to the BSA name was acquired by the Canadian Aquilini family. BSA Co. was sold and a US company (Bill Colquhuon's BSA Co.) used the name for Rotax-engined military bikes and Yamaha-based Bushman machines for developing nations.
In 1991 BSA Company merged with Andover Norton International Ltd., to form a new BSA Group, largely producing spare parts for existing motorcycles. In December 1994 Colquhoun and Jackson's BSA Group was taken over by a newly formed BSA Regal Group.
The new company, based in Southampton, has a large spares business and has produced a number of limited-edition, retro-styled motorcycles.