Capper was born on March 2nd 1901 to a Jewish family, refugees from persecution in Lithuania and became a very active Communist trade unionist, working mainly within the National Union of Teachers, although he was also a member of the Incorporated Association of Assistant Masters.
By his teens be had become a socialist and an atheist. In 1917 he obtained a scholarship to Kings College, London to read French, and he subsequently obtained a teaching certificate. In 1920 he attended the founding convention of the Communist Party of Great Britain.
Despite his abilities, Capper’s career as a teacher from 1922-1966 was chequered and insecure, mainly due to his membership of the Party and the Teachers Labour League; he was involved in the latter from at least 1928. For example, in 1931, Capper lost a teaching post at Gillingham, Kent.
He became the Secretary of the Central Committee of the London Teachers Association during World War Two; this was the County Association of the National Union of Teachers that continued to operate in the capital until evacuation in 1943.
His linguistic skills contributed to his appointment as International Secretary of the Teachers Labour League. A consistent concern for Capper was the excessive influence of religious establishments upon the educational system. In this area he seems to have played a significant part in shaping Communist Party and NUT input into the negotiations preceding the 1944 Education Act.
Capper taught at Battersea Grammar School from 1945 to 1956. He took a post as Assistant Master at this voluntary aided school and continued to be very active in the London Teachers Association. He was primarily teaching Geography rather than French, his degree subject. This rendered him vulnerable to an attack in 1953, when the Head asked him to transfer to another LCC school.
Capper got the support of both the LTA and the IAAM and the school’s Staff Society voted overwhelmingly against a plan to put the transfer proposal to the Governors. Capper made strenuous efforts to seek other LCC posts before, during and after this crisis. Capper was involved with the Humanist Teachers Association from 1954 to his retirement and was secretary of the Lambeth Teachers Association in his later years. He died on 10th June 1974.
Main source: http://www.wcml.org.uk/tu/nut_capper.html
Note: The Working Class Movement Library has an archive of material sent to the Library by David Capper’s wife and fellow teacher, Nan McMillan, after his death in 1974. (See entry for Nan McMillan.)