To modern thinking, the idea of carrying, on a motor vehicle, a clumsy furnace burning charcoal to provide wood gas, also known as producer gas, for fuelling the vehicle, seems quite ludicrous. However, this was a situation which confronted many vehicle owners and operators during World War 2, when petrol rationing was imposed in October, 1940. Petrol, along with so many staple necessities such as clothing, tea and sugar, was rationed to limit civilian consumption and so, make these items more available for the fighting forces. Money alone was not sufficient to effect a purchase of rationed goods for civilians; the correct ration coupons were also required. 

During this period, there was a decrease in the number of vehicles registered, as a good number of private car owners put their cars up on blocks, in storeage; some folk reverted to horse transport. Private users could eke out their rationed amount by limiting their running but those business users who had to keep their vehicle on the road regularly, were faced with depressing prospects. One method of extending their ration, which some users tried, was to add the then-common power kerosene, as used in tractors and engines, to the petrol. Cold engines were started on petrol and were switched over to the mixture after being warmed up. However, as this had not had the road tax component added to its price, it was actually illegal; it was also almost impossible to conceal, as the exhaust of an engine using kerosene gave off a most distinctive and pungent smell. In 1942, all petrol marketing and distribution arrangements were abandoned, with the aim of reducing delivery and administration costs, and replaced by an industry-wide single marketer named Pool Petrol, in which all the companies were shareholders.