Casswell was a motorcycle produced in 1904, by a London firm that was located at 29 Great Eastern Street, London.
The Engineer in the latter half of 1954 mentions J.S. Caswell, which may be a typographical error.
In 1904 the company exhibited a machine at the Crystal Palace show. It had a 3½hp Fafnir water-cooled engine mounted in a Chater-Lea frame. The radiator went flat beneath the fuel tank and the transmission was by chain to a two-speed gearbox with clutch. Nothing further was heard of it.