THE earliest experimental work in connexion with the telephone and telegraph services of the General Post Office is recorded to have taken place in 1878. It was, however, not until 1904 that one or two members of the Engineering Department were relieved of their administrative duties to enable them to pursue investigations of a purely experimental nature in a room set aside for the purpose in the Central Telegraph Office. In 1909, the ‘Research Section' was recognized as a separate entity, and additional laboratories in a nearby building were allotted to it. Natural expansion of the section, curbed during the First World War, was accelerated when hostilities ceased, and a site of eight acres was acquired for a research station at Dollis Hill in northwest London and about seven miles distant from the Central Telegraph Office. The work was transferred to this site in 1921, when the accommodation took the form of ex-army huts ; the present permanent buildings were formally opened in 1933. The activities of the Research Station expanded steadily during the inter-war period, and during the Second World War they were diverted to deal almost entirely with objectives having immediate military application. Arrears of normal development of research for the Post Office‘s services now require an accelerated expansion, which is being effected as rapidly as present circumstances permit.