This was designer Ted Martin's masterpiece - a twin ball-race 3.5 cc diesel which immediately became the performance standard in its class upon its introduction in August 1951. It was manufactured by the Anchor Motor Co. of Chester, England, but only remained in production by that company until April 1952, when the AMCO range was sold to the Aeronautical Electronic & Engineering Co. of Alperton in Middlesex. It remained in somewhat limited production by that company right up to the end of all AMCO production in early 1955. A significantly revised variant appeared in very small numbers immediately prior to that unhappy event.
The full history of the AMCO range may be found in my earlier article on the subject on the "Model Engine News" (MEN) web-site.