Before the First World War munitions supply was largely a matter for the individual services, although the Ordnance Office and later the War Office had supplied certain naval ordnance and small arms for the Admiralty. By 1915, however, the question of munitions supply, especially of high explosive shells, had become critical. On 8 April a Cabinet committee, the Munitions of War Committee, was set up to secure the maximum employment of the resources of the country on the manufacture and supply of munitions of war. It worked through a War Office committee, the Armaments Output Committee, which had been set up a week earlier. This arrangement was superseded by the formation of a Ministry of Munitions on 9 June 1915.
From its establishment, the ministry furnished the War Office with light and heavy arms, ammunition and explosives. The Trench Warfare Supply Department was responsible for the supply of novel trench warfare stores. The ministry's responsibilities also covered questions of labour in the munitions industry, contracts and the administration of the National and Royal Ordnance Factories. The ministry did not supply the Admiralty with one significant exception.
Early in 1917 the ministry took over from the Admiralty and the War Office responsibility for the supply and inspection of aeroplanes, seaplanes, engines and accessories. An Aircraft Production Department was therefore set up. Questions of design, requirements and allocation passed to the ministry in January 1918 following the dissolution of the Air Board. After the war the supply of army equipment and subsistence also passed to the Ministry of Munitions.
As the functions of the ministry expanded and its responsibilities extended, the number of departments in it multiplied from four to over fifty. In August 1917 there was a major reorganisation; the departments were arranged into eleven main groups which subsequently varied little. The heads of these groups, with the minister of munitions and the parliamentary secretaries, constituted the Munitions Council.
In November 1918 proposals to turn the ministry into a centralised supply ministry were overtaken by the Armistice. In view of the enormous stocks of war material left over from the War, the supply problem lost its urgency and this, together with opposition from the Admiralty and the Air Ministry, led to the abandonment of plans for such a ministry. Instead the powers of the Ministry of Munitions were reduced and dispersed.
As its responsibilities covered an enormous area of administrative direction and control, the work of a large number of central government departments was affected. In May 1918 the Ministry of National Service had taken over the supply of building labour and the issue of licences; the following November control of labour legislation passed to the Ministry of Labour. Design and research returned to the War Office in March 1919; this was supplemented in June 1920 by the transfer of responsibility for Army supply and control of the Ordnance Factories.
In January 1920 the Air Ministry took over the supply of aircraft. In the summer of 1919 the Board of Trade inherited a large number of administrative responsibilities from the Ministry of Munition, including the Mineral Resources Development Department and the Optical Munitions and Glassware Branch. Other diverse responsibilities passed to the Ministries of Shipping and Transport respectively. The Office of Works became involved in the case of unsold properties and took on other functions in the housing area in July 1920.
On 31 March 1921 the Ministry of Munitions was finally wound up. Its remaining powers, duties and property were transferred to the Treasury and responsibility for the work of liquidation and disposal was vested in a Disposal and Liquidation Commission appointed by that department. The commission's work ended at the end of March 1924; the disposal of remaining surplus government property and the completion of the winding up of contracts were vested in a Treasury department, the Surplus Stores etc Liquidation Department.