By 1911 he had moved to new premises in Tariff Road,[1] within the Northumberland Park area of Tottenham, London, and which still exists as of 2015.

[4] During WWII Prestwich produced around 240,000 industrial petrol engines in support of the war effort, together with millions of aircraft parts, fuses, etc.

A. Prestwich Industries Limited which was registered on 23 April 1951 and floated on the London Stock Exchange shortly after.

[12] Machines that incorporated its engines included the AJS Model D, fabricated for the Russians in the First World War.

[13] JAP exported significant numbers of engines to foreign motorcycle manufacturers including Dresch[14] and Terrot in France, and Ardie,[15] Hecker[16] and Tornax[17] in Germany.

Latterly, JAP engines (under Villiers control) were used in motorcycle racing, and most commonly speedway or dirt track.

Variants included the use of 4 valve heads, twin spark plugs and early electronic ignition systems.

[23] Cooper cars powered by JAP engines won the British Hill Climb Championship for eleven consecutive years.

[26] Early models of the railway maintenance ganger's Wickham trolley, from 1948, used a vee-twin JAP engine.

[27] In the 1950s other Wickham trolleys used the 600 cc JAP engine and drove through a clutch, tail shaft and bevel drive.

A. Prestwich also made small utility engines under the JAP name for a variety of uses, both stationary and in motorised equipment.