He was the son of Sir William Haldane and his wife Edith Nelson.
In 1919 he went to Trinity College, Cambridge and worked at the Cavendish Laboratory under Rutherford.
In the summer of 1932 he was a member of a Fabian Society group which visited the Soviet Union, where he studied power stations and energy supply.
In the following year he contributed the chapter on "Power and Industrial Developments" to a book entitled Twelve Studies in Soviet Russia edited by Margaret Cole.
[1] In 1948 he was President of the Institution of Electrical Engineers and won its James Watt Gold Medal in 1953.