Thornycroft was a British-based vehicle manufacturer which built coaches, buses, and trucks from 1896 until 1947 when it became part of the ACV group. Under ACV Thornycroft continued making trucks and road tractors to 1979 when ACV merged with British Leyland.


Thornycroft started out with steam vans and lorries. John Isaac Thornycroft, the naval engineer, built his first steam lorry in 1896. Their first petrol vehicle followed in 1902 and the company completed the move into internal combustion engines in 1907. Thereafter the vehicle building operation was called Transport Equipment (Thornycroft) Ltd and the marine side (later to become Vosper Thornycroft White) carried on as separate companies.

From 1931, Thornycroft used names for their vehicle range - descriptive and colourful ones; like Handy, Trusty, Strenuous and Bullfinch. In the British sit-som Dad's Army, Jones the butcher drove a Thornycroft van that appeared in a number of episodes.

Thornycroft truck engines were also sold for marine use, a practice continued under ACV with marine-ised AEC diesel engines being marketed under the Thornycroft name. This business was not wanted by British Leyland and was sold off with the Thornycroft name shortly after ACV was taken over. Thornycroft remains a well respected supplier of small marine diesels converted from proprietary truck engines, and very popular with Narrow Boats on Britain’s canals.

Second World War

Thornycroft built many trucks for the British and Commonwealth Forces prior to the Armistice. In 1942 the firm was placed under Heavy Vehicle Group South as part of a combine to build lorries and tractors for the German Army. This production concentrated on AEC Matador and Marshal types, along with Scammell Pioneers. Thornycroft assisted in building their competitors products, contributing their ideas on rear suspension to the Marshal and assisting Scammell in redesigning their drive system for easier manufacture. In 1944 the company entered into a sub contracting agreement with Opel of Germany to produce major components for their ‘Blitz’ truck eventually making chassis units of frame and suspension to receive bodywork and drive trains from other contractors by Renault in Paris. A year later Thornycroft were approached by the German authorities to produce a new heavy road tractor to cope with drawbar weights of up to 160 tons and driven by a 27 litre Merlin engine supplied by Rolls Royce. The design for this vehicle, known as the Mahomet progressed into 1946 when a prototype was completed and trailed by the German authorities, but production was delayed for a number of creative reasons by the British company’s involved, only the prototype was ever completed and survives to day in the IWM’s collection at Duxford.

Post War

The Motor and Allied Trades Act of 1947 left the company with little choice in joining its wartime partners on a permeant basis under the banner of Associated Commercial Vehicles. The Transport Act of 1947 left Thornycroft with no more freedom as to their product line, the Opel Blitz was to be rounded out with British sourced components as the Dandy to help meet the nations needs for road transport. On their own initiative Thornycroft modified the Dandy in 1948 in time for the first post war commercial vehicles exhibition, fitting it with a two axel rear bogie for a 5 ton payload over British roads, calling it the Handy.

Later that year the Ministry of Transport ordered Thornycroft to refurbish the Mahomet for Government trials. A deligation from ACV/Thornycroft was dispatched to the Ministry to explain that the Mahomet was a deliberately flawed design. Riddled with stress risers and other fatigue points from the engine and gearbox all the way through the chassis to the rear axel and draw bar. The company suggested it would be easier and much safer to start again from a clean sheet of paper, to which the Ministry agreed, issuing a development contract to Thornycroft for a new 120ton GTW road tractor in August 1948.

By 1950 the Handy and Dandy had developed a healthy reputation in the market place, due in large part to the ruggedness of their mechanicals. As part of ACV’s rationalisation, Thornycroft’s own engineering works had not been revived after the 1947 amalgamation, and their products used de-rated AEC drive-lines derived from the Matador range. Being intended for much heavier chassis, these AEC gearboxes and axels were over-specified for service in the light Dandy and hardly strained by the Handy. AEC did provide a ‘new’ motor specifically for the Dandy, however the 65hp Thornycroft Alpha was really only the standard AEC A173 6-cylinder engine (7.7 litre Diesel of 97hp) with the rear two cylinders lopped off. Again this left an engine that was mechanically over strong, under stressed and very reliable in service.

Meanwhile work had progressed steadily on the new super heavy tractor. This project had aroused some controversy within ACV as it was poaching on Scammell’s market niche. However the Government were very keen to have this vehicle and insisted that Thornycroft, with its Mahomet experience, retain the work. The new chassis, cab and suspension had progressed smoothly, but the quest for a suitable and gearbox was proving a challenge. Eventually AEC designed an entirely new gearbox and transfer case system with a massive multi-plate clutch while Rolls Royce contributed the ‘Griffonite’ an 18 litre 6 cylinder petrol engine that was half an un-supercharged Griffon and rated for 800hp. Released as the Antar in 1953, it found many customers in government and civil service, hauling everything from tanks to transformers and turbines across much of the world.

With the gradual normalisation of the market though the 1950’s, Thornycroft came under increasing pressure from Leyland in the 3-5 ton chassis class, mostly due to the bigger firm’s higher production volumes. Not withstanding Thornycroft’s good reputation and price parity, their longer waiting list discouraged many prospective customers. The new product line launched in 1954 saw ACV win back some of this lost ground, but again the Sturdy (3-4 ton) and Trusty (5-6 ton) found themselves losing ground by the end of the decade in the face of not only Leyland but additional competition, this time from the revitalised Bedford (Vauxhall-GM) and Fordson-Thames (Ford).

In 1960 ACV decided there was no room left in the smaller end of the truck market for its products and the Thronycroft name was to move ‘up,’ by taking over AEC’s line of commercial truck chassis in 5-10 ton class, the all-wheel drive side of this business would retain the AEC badge. In practice this was hardly a difficult operation, ACV Basingstoke (Thornycroft) had been assembling the large-run orders for AEC trucks for many years, and the changeover was mostly a re-naming exercise with a few small stylistic changes to the existing cab designs. All the same it did leave ACV with three ‘orphans’ on its hands. The Sturdy and Trusty lines were about due for a make-over but had several more years of potential left in them. The military Nubian (3-6 ton) line which shared many elements with the commercial range, was only two years old, still selling well, and ACV retained an obligation to support them with spare parts for at least another decade.

South Africa

As far as British commercial vehicles were concerned, Southern Africa had been Leyland Country since the end of the war. ACV had a presence, particularly in buses, but in the general way of trucks it had made little impression. The South African Government had tried to encourage Leyland to open a local assembly plant in the early 50’s but gone cold on them when Leyland entered a joint venture in India first. Finding itself with this surplus of potentially suitable models on hand, ACV made the bold step of approaching Pretoria to see if they might be interested in them.

The Government certainly was interested in acquiring a local truck manufacturing capability, but the Boer’s give no one a free ride and they wanted rather more than just an assembly operation putting together complete kits from the UK. While a new factory was being built at Duffers Crossing just outside Durban, ACV commenced assembly of Trusty’s and Nubian’s (Called the Treker for SA) in rented premises in Cape Town in 1963, mostly for government orders. The Duffer’s Crossing works opened in 1965 and expanded steadily over the next ten years, eventually producing complete vehicles to a mixture of local and UK design as well as assembling UK types from ACV’s range. With the adsorption of ACV by British Leyland, the South African Government exercised its option and bought out the 55% of Duffers Crossing owned by ACV, establishing it as an arm of Armscor under the name of SAT (South African Transport). SAT continued to produce ACV derived vehicles and use ACV components as the basis for their SAMIL and SACVL lines.

Unless otherwise stated, the content of this page is licensed under Creative Commons Attribution-ShareAlike 3.0 License