During the First World War some 248 million shells were used by the British Army and the Royal Navy. The basic propellant used to fire these shells, and for a whole host of other military purposes, was cordite. This propulsive explosive was made from some form of nitrocellulose, cotton waste being the material used, mixed with nitrated glycerine. The solvents used in manufacturing cordite were acetone and ether-alcohol.

Acetone was produced almost entirely by the destructive distillation of wood, and the world market in this commodity was dominated by the great timber growing countries. Before the war the acetone used in the UK was mainly imported from the United States.  British manufacturers simply could not compete successfully with foreign makers and our own plants were both small and antiquated. In 1913 a modern factory had been established in the Forest of Dean, but by the outbreak of the war in August 1914 the stocks of acetone for military use stood at only 3,200 tons and it was soon apparent that this and existing production would not meet the rapidly growing demands.  It was found that acetone could be produced from potatoes and maize and new plants were erected to undertake this work.

By 1917, however, the German submarine offensive in the Atlantic had threatened to cut off supplies of North American maize.

Faced with the possibility of a serious maize shortage, experiments were begun to find a substitute for it in acetone production and it was discovered that the horse chestnut could be used as an alternative. Factory experiments were set in hand and the site chosen for the project was the Synthetic Products Company's facility at King's Lynn, which had been converted for the production of butyl-alcohol and acetone from potatoes in 1915.  Successful results indicated that the manufacture of acetone from horse chestnuts could be achieved and the Ministry of Munitions commenced the task of organizing the collection and transport of 1917 horse chestnut 'harvest'.

A statement in The Times of 26 July 1917 read, "chestnut seeds, not the green husks, are required by the Government for the Ministry of Munitions. The nuts will replace cereals which have been necessary for the production of an article of great importance in the prosecution of the War".  The major method of collection was to enlist the aid of school children.

Vast quantities of horse chestnuts were collected but only 3,000 tons reached the King's Lynn plant. Collection was restricted by transport difficulties, and letters in The Times tell of piles of rotting horse chestnuts at railway stations.

The columns of The Times also reflect another aspect of this story.  Nobody really knew why they were collecting horse chestnuts. The government was, naturally, reticent to reveal the motive behind its scheme since the Germans could very well copy this novel form of acetone production.

A question was even asked in the House of Commons but the answer given simply stated that they were required for "certain purposes".  The veil of secrecy drawn over the horse chestnuts' final use even led to accusations that voluntary effort was being used to provide personal profit.

After initial difficulties the King's Lynn factory began production using horse chestnuts in April 1918, but the work was hampered by the basic fact that the horse chestnuts were poor quality material from which to produce acetone, and production ceased again in July 1918.

The Autumn of 1917, however, is still remembered by many as the time when they collected conkers for the Ministry of Munitions.

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