Marcos Engineering was founded in 1959 by Jem Marsh and Frank Costin, whose surnames combine to give the company its name. Their first prototype, the Xylon, was built at a garage in Dolgellau, North Wales. In 1963 the company moved to a converted mill, Greenland Mills, at Bradford-on-Avon in Wiltshire.
Costin, who had previously worked on the de Havilland Mosquito fighter-bomber, gave early Marcos cars an unusual chassis built from laminated marine plywood, glued together from hundreds of individually cut pieces. The resulting Marcos GT, shown at the 1963 London Racing Car Show and sold from 1964 with a Volvo engine, was light and strong, and Marcos cars did well in production-car racing. The plywood chassis was gradually replaced by a steel one from 1969. The fibreglass-bodied Mini Marcos, a kit car built on Mini running gear, was the only British car to finish the 1966 24 Hours of Le Mans.
Marcos moved to a new purpose-built factory at nearby Westbury in 1971, funded by the Rob Walker Group after the company’s first bankruptcy. It went through further reorganisation in 1972, and Jem Marsh bought back the rights to the Marcos name in 1976, relaunching the brand in 1981 with the V6-engined Marcos coupe, sold in kit and factory-built form. The company went bankrupt again in 2000; a further revival followed in 2002, when Tony Stelliga and Marsh formed a new Marcos Engineering Ltd and moved road car production to Kenilworth, Warwickshire. The company finally went into voluntary liquidation on 9 October 2007, and the Marcos name has since been the subject of competing revival claims.