The National Service League was a British pressure group founded in February 1902 to alert the country to the inadequacy of the British Army to fight a major war and to propose the solution of national service.
The League argued for four years of compulsory military training for home defence for men aged between eighteen and thirty. Compulsory military service, conscription, was not popular and "aroused the long-standing antipathy toward standing armies and smacked of continental-style militarism". By October 1904, it had only 1,725 members and 2,000 in 1905 but membership grew to 21,500 in December 1908 and it claimed a further 30,000 "adherents". The circulation of the League's journal, The Nation in Arms, grew to 17,500. By 1910 the League had 60,000 members. The NSL Annual Report of 1913 stated that the 'total of subscribers', which included members and associates, was 96.526 and the 'number of adherents' was 163,746. The Annual Reports of 1908 and 1913 commented that the number of local NSL branches in the country were 33 and 45 respectively. Fear of Germany and a possible German invasion of Britain, coupled with the belief that the Army and not the Navy could stop an invasion underlaid many of the League's proposals.
Although Churchill and Lloyd George (both Liberal Cabinet Ministers) sometimes expressed private support for conscription, the movement to introduce it was largely a right-wing one. It was thought that it would encourage national regeneration in spite of the election of Labour MPs from 1906, industrial unrest, agitation for women's suffrage, and the Liberal Government's removal of the Lords' veto of legislation.
Its first president was Lord Raglan; in 1905, he offered the presidency to Lord Roberts, who accepted.