The company, J.A. Prestwich Ltd., was founded in 1895, when Prestwich was in his early 20s. He commenced manufacture of scientific instruments, initially behind his father's house at 1 Lansdowne Road, Tottenham, London. By 1911 he had moved to new premises in Tariff Road, within the Northumberland Park area of Tottenham, London.
In 1919 Prestwich formed Pencils Limited to exploit his invention of new machinery and the company made Master Pencils (Black Lead and Coloured Crayon Pencils), also in Tariff Road.
JA Prestwich Industries was formed in 1951 by the amalgamation of J.A. Prestwich and Company Limited and Pencils Ltd. and floated on the London Stock Exchange shortly after.
By 1957 practically all the shares in the company had been acquired by Villiers Engineering Company Limited of Wolverhampton, which also made motorcycle and industrial engines. The engineering works in Northumberland Park closed in 1963 and J.A. Prestwich Industries Limited was liquidated in 1964.

John Alfred Prestwich (1874 - 1952) was an English engineer, designer, and businessman. He is famous for a number of his designs, which included much of the early cinematography equipment, and worked with such luminaries as S.Z. de Ferranti and William Friese-Greene (the cinema pioneer).
Cinematographic equipment including cameras, printers, mutoscopes, cutting and perforating machines, and projectors, such as the Bioscope projectors for the Warwick Trading Company and Charles Urban, were produced by the company in the early part of the 20th century.

But for classic motorcycle enthusiasts, he is best known for the range of motorcycle engines his company produced.

The company specialized in precision engineering which led to the development of their first motorcycles—engines. Complete machines were manufactured between 1904 and 1908.

Although his engines powered motorcycles of his own design for a short time, they earned a reputation for power and reliability needed by other manufacturers. The first motorcycle engine developed and sold by J.A.P. was a 293-cc unit produced in 1903 which was used by the Triumph company for their motorcycles. Customers for the J.A.P. engines came, not just from motorcycle manufacturers, but aircraft manufacturers and industrial companies, too. Early aircraft were light and basic, and needed a reliable and lightweight engine to power them. JAP motorcycle engines were often used in this application. A J.A.P. engine was used in A. V. Roe's 1909 triplane, regarded as the first all-British aircraft, and for a while Prestwich and Roe had a partnership. J.A. Prestwich at first would deliver the same engine to the aircraft manufacturer, allowing them to make local modifications – mainly larger venturi tubes for the carburettor, to allow for greater air intake at altitude. But in the late 1920s/early 1930s J.A. Prestwich produced various heavier engines under licence, including those for the UK market for Aeronca.

J.A.P. engines were also exported to many countries including the French Terrot and Dresch manufacturers, Ardie, Hecker, and Tornax in Germany, and many manufacturers in Australia such as Invincible.

Customers from the motorcycle manufacturing industry included Brough Superior, Cotton, Excelsior (the British company), Triumph, HRD, Matchless, Zenith and Royal Enfield among others.
Royal Enfield used the 6hp 770cc and later 8hp 996cc v-twin engines for there model series 180-195.

Two engines stand out from the many produced by J.A.P. because of their contribution to motoring in general and motorcycling in particular. The first is the V-Twin which was manufactured in various capacities from 1905. The V-twin was used in their own motorcycles from 1906.

The main advantages of the J.A.P. V-twin engines were their excellent power to weight ratio and reliability. Although important to motorcycle manufacturers, these attributes were seen as critical to aircraft manufacturers many of whom used J.A.P. engines.

For motorcycle use, the V-twin engine had another attribute: narrowness. With the obvious need to lean a motorcycle over for cornering, the narrower engines were ideal for giving more ground clearance.

One of the most popular motorcycle sports in the UK and Australia was Speedway, which along with grass track racing was dominated for many years by J.A.P. engines (records show J.A.P. engines were still being used in the 1960s).

Due to the unusual tax laws in the UK, three-wheeled vehicles were taxed the same as motorcycles and many J.A.P. customers used the engines for sidecar work.
JAP engines were extensively used in cyclecars in the 1910 to 1914 period when they were very popular with large numbers of small manufacturers. In 1914 JAP announced a new engine made specifically for the cyclecar, which was a V-twin of 90mm bore and 85mm stroke (1082cc). The engine had a larger flywheel than the motorcycle engine and an enclosed magento drive and was among others also used in the popular three wheelers of Morgan cyclecars. Although more like a car than a motorcycle and sidecar, the Morgans were classified for tax purposes the same as sidecars. The engines were front mounted in the Morgan’s and many of the J.A.P. variants were used, including singles, twins, V-twins side valve and OHV configurations. In conjunction with Morgan, a water-cooled V-twin version was also available.

During WWII J.A. Prestwich supplied close to one-quarter of a million petrol powered engines in support of the war effort, in addition to millions of aircraft parts, fuses, etc.

In light of J.A.P.'s development of high powered but light engines for speedway, some low volume pre-war car manufacturers, including G.N., T.B., Morgan Motor Company and Reliant, used JAP engines to power their vehicles.
This use of the J.A.P. extended into motor racing after World War II; most were used in specialist UK lightweight formulas, or more extensively in Formula 3 racing after developments by John Cooper.

In its later life, J.A. Prestwich Industries also produced components for other vehicle manufacturers, including the cylinder head for the Lotus Cortina and the early versions of the Ford-based Lotus Elan engine.

The versatility of J.A.P. engine design can be seen in their stationary engines, which have powered a wide array of industrial equipment such as generators, rotavator, water pumps, milking machines, lawnmowers, hay lifts and numerous machines in the agricultural industry.
Most were 4-stroke, but there were some 2-stroke engines and they were quite reliable. J.A.P. also had a factory in Chelmsford Road, Southgate, London, employing 40 to 50 people, where these engines were being made from 1955.

In 1957 Villiers, another manufacturer of engines absorbed J.A. Prestwich Industries.