Messrs. Andrew Barton Brothers of Beeston, pioneers in the production of flexible gasbags, had converted 700 vehicles to gas, including motorbikes and tractors, in the fifteen months up to September 1917, when it was claimed they were the first to fit one to a Beeston omnibus.

The Countess of Arran’s 1917, 25h.p. Lanchester landaulet fitted with a neat collapsible gas container made by rivals Spencer-Lyon Ltd., balloon makers of London, was shown at an Olympia exhibition.

One wag in 1917 reckoned that a bag of coal gas on the roof would reduce the weight of the car and hence road adhesion, so causing tyre trouble but was corrected when it was pointed out that 250 cubic feet of gas would only give 10lbs of lift; less than the weight of the rubberised bag.

Because too many petrol-rationed drivers fitted them, the government brought producer/coal gas use for cars into rationing regulations after 1917, although there was a glut of it as a by-product of carbonising coal for munitions. There followed changes to the regulations for vehicles towing gas-bag trailers too, to permit those to exceed the normal 5mph limit. Gas bags had all but disappeared by mid 1919.

Many drivers were fined for illegal use of gas. Even Sir Thomas Beecham was fined £5 in March 1918 for contravening the Petrol and Gas Restriction Order in his gas-powered car on the way to Drury Lane Theatre.

My doctor used this system on his Austin 7 when he did his rounds in 1945/6. Being a city doctor, his rounds would not have entailed a high daily mileage. From memory, the gas bag looked as big as the car and extended forward of the windscreen.

The use of gas for road vehicles was very popular during WW2 here in France. A fellow I met, not far from where I live now, still makes a conversion for a gasogene, he has one fitted to his old Citroen truck.

It's funny, I just checked the registration document for one of our modern cars, and the French documents still show a category for Gasogene today. Perhaps they are hedging their bets, just in case the government can get some additional tax from road users!!!