The test report concluded. With the new vehicle being the only diesel-engined 6-tonner on the market which could legally travel at30 mph, and which had an on the road price of well under ?1000, the Seddon proved to be an immediate success. Production quickly rose to seven or eight garage door opener quietest each week and by the outbreak of the Second World War in 1939 there were more than 200 Seddon 6-tonners on the road. However production of the lorry came to a halt after the outbreak of war due to shortage of the major components and instructions from the Ministry of Supply that the company was to produce trailers for use by the military.
The companys venture into the truck manufacturing business seemed destined to be a rather short-lived affair but having started to build the required garage door opener quietest as instructed, the Ministry then issued new instructions ordering the company to build a number of trucks. These were to be for civilian use and the completed vehicles would be allocated to users by the Ministry of War Transport. The numbers involved were not large with only three vehicles allowed to be completed each week so the remaining capacity of the workshops continued in the production of Army trailers. It was during the war years that the company also received its first export order with five chassis built for use by a firm in Cyprus.
It appears that although the order was completed and the chassis delivered to the docks at Tilbury this was as far as they got as they were subsequently destroyed by a German air raid. Despite production restrictions and the shortage of materials during this difficult time the company was able to develop new models and in the spring of 1940 a new short-wheelbase chassis was introduced. The 9ft wheelbase chassis was primarily designed for use as a tipper or as a 9-10 ton tractor unit and the basic design incorporated the main elements of the very successful 6-tonner. It was powered by the Perkins P6 with a new very garage door opener quietest five-speed gearbox. The robust 8in deep steel rails and cross-members had been used for the chassis.