Sampson was born at Kensington, London on 6 September 1896, son of Samuel Arthur Sampson, LL.D, a Trinity College, Cambridge-educated barrister of Lincoln's Inn (son of Samuel Sampson of Hendon, Middlesex, also a barrister of Lincoln's Inn), and Nina, daughter of Frederick S. Hull, of Liverpool.
[1][2][3] He was educated at Rugby School, Warwickshire, and entered the British Army at the age of eighteen with the outbreak of the First World War, serving as an officer in an infantry battalion and in the Machine Gun Corps.
At the end of the war after three years in France he worked for a firm of chartered accountants in the early 1920s and then later set up his own practice.
In the Second World War, he was recalled to the army and became an auditor with the Admiralty in London, a position he retained until his retirement in the 1950s.
[4] He was a Fellow of the Institute of Chartered Accountants in England and Wales (ICAEW).