Marcos was founded in Dolgellau, North Wales, in 1959, by Speedex cars' Jem Marsh with aerodynamicist Frank Costin. Costin had earlier worked on the de Havilland Mosquito fighter-bombers and from there he got the idea to use plywood for the chassis. The company moved to a converted mill in Bradford on Avon, Wiltshire, in 1963; in 1971 they relocated to a £125,000 purpose-built factory at nearby Westbury.