Clifford Allen was born in 1889 in Newport, Monmouthshire, Wales, and brought up in Bristol. He was educated at Berkhamstead School, University College, Bristol (later Bristol University) and then as an exhibitioner at Peterhouse College, Cambridge. Living in Chelsea, London, he worked as a journalist, becoming manager of the Daily Citizen, a socialist newspaper, 1911-15. When Fenner Brockway suggested a No-Conscription Fellowship in 1914, three months after Britain had entered what became the First World War, Clifford quickly joined this attempt to stop the possibility of compulsory enlistment in the Army, organising his local branch in Chelsea, and becoming chair of the national committee. The passing of the Military Service Act in January 1916, despite the efforts of the No-Conscription Fellowship, prompted Clifford and others to sign a leaflet, Repeal the Act, leading to prosecution of the signatories excepting Clifford, although there was no obvious reason why he was left out.

Clifford appeared before the Battersea Local Tribunal on 14 March 1916, requesting absolute exemption as a CO, but was given only exemption from combatant service, meaning a requirement to serve in the Non-Combatant Corps; he went to the London Appeal Tribunal on 10 April, where he was exempted on condition of doing Work of National Importance. Clifford asked the Pelham Committee, overseeing such work, to allow him to continue his peace work, but the Committee refused, and when after three weeks the impasse had not been resolved, the Local Tribunal reinstated the original non-combatant decision, leading to a notice to report to the army on 30 June 1916. Clifford ignored this, resulting in a warrant for his arrest by the civil police, and Clifford voluntarily surrendered himself at Lavender Hill Magistrates’ Court on 31 July to contest the validity of the Local Tribunal’s re-imposition of non-combatant service. The Court ruled against him, and handed him over to the military.

Taken to Warley Barracks, Essex, he refused to put on uniform, but, contrary to regulations, was forcibly dressed in khaki, and, deemed enlisted in 7 Eastern Company, Non-Combatant Corps, court-martialled on 18 and 23 August 1916, and sentenced to two years imprisonment with hard labour, commuted to112 days. Admitted to Wormwood Scrubs Prison, he appeared before the Central Tribunal on 20 September, and told them he would not consider the Home Office Scheme. On medical examination , he was found fit only for light work (indicating that exemption from military service on medical grounds might well have been granted). Released on 25 November, he was taken to Newhaven  Fort, where he again disobeyed orders, and had a second court-martial on 12 December, and sentence of one year imprisonment with hard labour, commuted to six months, served in Maidstone Prison; the cycle continued with a third court-martial at Park Hall Camp, Salisbury Plain, on 15 May 1917, two years imprisonment with hard labour, served in Winchester Prison. Questions were asked in Parliament as his health deteriorated, and on 6 December 1917 he was released to a nursing home in Bournemouth, where he stayed until contracting pneumonia in February 1919, necessitating removal to a hospital in London.

Eventually Clifford returned home to resume life, but his health never fully recovered. He served as Treasurer and then Chair of the Independent Labour Party, 1922-25, Chair of its paper, the New Leader, over the same period, and a director of the Daily Herald 1925-30. In 1932 he was invited by Ramsay Macdonald, to support ‘National Labour’ (the rump of the Labour Party that Macdonald had taken with him on his forming the controversial ‘National’ government in August 1931) in the House of Lords, and Clifford became Lord Allen of Hurtwood. By winter 1938-39, having developed tuberculosis, he went to a sanatorium in Montana, Switzerland, where he died on 3 March 1939. His widow, Marjory, Lady Allen of Hurtwood, was influential in the cause of children deprived of a normal home life and the passing of the Children Act 1948 as a significant part of the post-WW2 establishment of the welfare state.