Editing Harold Macmillan (section)

===Canadian aide-de-campship===
Of the scholars and exhibitioners of his year, only he and one other survived the war.{{sfn|Williams|2010|p=31}} As a result, he refused to return to [[University of Oxford|Oxford]] to complete his degree, saying the university would never be the same;{{sfn|Horne|2008|page=49}} in later years he joked that he had been "sent down by [[Wilhelm II|the Kaiser]]".<ref>Thorpe 2010, pp. 42–45; "sent down" is a university term for [[Expulsion (education)|"expelled"]]</ref>

Owing to the impending contraction of the Army after the war, a regular commission in the Grenadiers was out of the question.{{sfn|Williams|2010|p=49}} However, at the end of 1918 Macmillan joined the Guards Reserve Battalion at Chelsea Barracks for "light duties".{{sfn|Thorpe|2010|p=62}} On one occasion he had to command reliable troops in a nearby park as a unit of Guardsmen was briefly refusing to reembark for France, although the incident was resolved peacefully. The incident prompted an inquiry from the War Office as to whether the Guards Reserve Battalion "could be relied on".<ref>Macmillan 1966, pp. 107–108. This period saw disturbances amongst British troops in France, which was of grave worry to the Government as the Russian and German revolutions had been accompanied by army mutinies. In the end the crisis was resolved by giving priority for demobilisation to men who had served the longest.</ref>

Macmillan then served in [[Ottawa]], Canada, in 1919 as [[aide-de-camp]] (ADC) to [[Victor Cavendish, 9th Duke of Devonshire]], then [[Governor General of Canada]], and his future father-in-law.{{sfn|Horne|2008|p=52}} The engagement of Captain Macmillan to the Duke's daughter Lady Dorothy was announced on 7 January 1920.{{sfn|Williams|2010|p=55}} He relinquished his commission on 1 April 1920.<ref>{{London Gazette|issue=31958 |supp=y|page=7073|date=29 June 1920}} ''The London Gazette'' states that he held and retained the rank of lieutenant.</ref> As was common for contemporary former officers, he continued to be known as 'Captain Macmillan' until the early 1930s and was listed as such in every general election between 1923 and 1931.{{sfn|Thorpe|2010|pp=72, 76–77, 88, 109, 118}} As late as his North African posting of 1942–43 he reminded Churchill that he held the rank of captain in the Guards reserve.{{sfn|Horne|1989|p=155}}