Milne joined the Scottish Office as an Assistant Principal in 1921. After seven years he was promoted to be Private Secretary to the Permanent Under-Secretary of State at the Scottish Office. Two years later, he became Private Secretary to the Secretary of State and in 1935 he was promoted to Assistant Secretary to head up the Scottish Office's new Local Government Branch in Edinburgh, which was meant to enable Scottish people and institutions to meet with government officials without having to travel to the Scottish Office in London. Four years later, Milne was promoted to Deputy Secretary at the new Scottish Home Department, and he was promoted to become its Secretary in 1942. Milne's final promotion in the civil service was to be Permanent Under-Secretary to the Scottish Office, in which office he served from 1946 until his retirement in 1959. Milne wrote The Scottish Office in 1958, a guide to its organisation and operation. In retirement, he was a Governor of the BBC in Scotland and Chairman of the Scottish National Orchestra Society. He had been appointed Companion of the Order of the Bath in 1942, and was promoted to Knight Commander five years later, followed by Knight Grand Cross in 1958. He died on 4 February 1972; his wife, Winifrede, had died two years prior, leaving two children.
Assessment
Milne had what Ian Levitt called in the Oxford Dictionary of National Biography a "brand of comfortable unionism... his administrative style and ability to select deputies of similar mind did much to ensure that Scottish opinion felt able to work and prosper with the United Kingdom government." His obituary in The Times remarked that "Only those who were at Dover House in those days can appreciate how much his sympathy, his tact, and his capacity for getting into the mind of Ministers and acting as an interpreter between them and their civil servants contributed to the smooth running of the administration". Later while Milne was its Permanent Under-Secretary, the Scottish Office grew and increasingly came to argue for the peculiarity of Scotland and the need for its consideration during policy-making. This, Levitt argues, reflected Milne's desire to stem the growth of Scottish nationalism; the result was a series of concessions to Scotland in the 1940s and 1950s in the form of lower tax rates but equivalent spending to England.
