[1] She became known as Lady Dorothy from the age of eight, when her father succeeded to the dukedom of Devonshire, and the family moved into Chatsworth House, Derbyshire, and the other ducal estates.

Their lavish wedding, on 21 April at St Margaret's, Westminster, was attended by royalty, aristocracy and leading literary figures, and was hailed as the social event of the London season.

[4] Lady Dorothy was a dutiful political wife and the couple remained married and publicly together (despite her long-lasting affair with Conservative politician Robert Boothby) until her death from a heart attack at the Macmillan family estate at Birch Grove, West Sussex, in 1966.

She and Harold had four children: In 1929 Lady Dorothy began a lifelong affair with the Conservative politician Robert Boothby, an arrangement that scandalised high society but remained unknown to the general public.

[10] Campbell suggests that Macmillan's humiliation was first a major cause of his odd and rebellious behaviour in the 1930s then, in subsequent decades, made him a harder and more ruthless politician than his rivals Eden and Butler.