The BSA M20 was a British motorcycle made by Birmingham Small Arms Company (BSA) at their factory in Small Heath, Birmingham. Although initially viewed as a near failure by the War Office in 1936, the M20 evolved into one of the longest serving motorcycles in the history of British military motorcycling, as well as becoming the most numerous type produced for World War II with 126,000 in active service. Many are still in use around the world today.