David Douglas, 12th Marquess of Queensberry

Under the Peerage Act 1963 which came into effect in August that year, all Scottish peers were given seats in the House of Lords as of right. This right was lost under the House of Lords Act 1999 which provided that "[n]o-one shall be a member of the House of Lords by virtue of a hereditary peerage." As a hereditary peer, Queensberry spoke in the House of Lords during the passage of the Sexual Offences Act 1967, which legalized homosexual acts in England and Wales. He explained in 2016 that he had been delighted to associate his family with a liberalising measure as "The Queensberry name had become so associated with the way Oscar Wilde was pilloried in 1895".

Queensberry's eldest but illegitimate son, Ambrose Jonathan Carey (b. 1961), is head of a British security and intelligence firm. His half-sister Caroline Carey (b. 1959), an English art student, married the late Salem bin Laden, prior head of the global Bin Laden family corporation. Ambrose Carey has been married since 1995 to Christina Weir, a daughter of the late Sir Michael Scott Weir KCMG (1925–2006) and his first wife, Alison Walker. They have two sons, Angus Carey-Douglas and James Carey-Douglas. As Ambrose is illegitimate, he and his two sons are not in remainder to the Marquessate and subsidiary titles.

Queensberry has been married three times: first in 1956 (div 1969) to Ann Jones (the actress Ann Queensberry), by whom he had two daughters; secondly in 1969 (div 1986) to Alexandra "Lexa" Mary Clare Wyndham Sich (daughter of Rev. Guy Wyndham Sich and Jean Denise Theobald), by whom he had three sons (the eldest born during his first marriage) and one daughter; and thirdly in 2000 to Hsueh-Chun Liao (廖雪君), by whom he had a daughter, legitimated by marriage (d. 2018).

He served in the Royal Horse Guards. In the 1950s he worked in the pottery industry. He was Professor of Ceramics at the Royal College of Art from 1959 to 1983. He belongs to the Crafts Council, was President of the Design and Industries Association from 1976 to 1978, is a Fellow of the Chartered Society of Designers (and recipient of the Minerva Medal, the Society's highest award), and was Senior Fellow of the Royal College of Art from 1990, and Professor of Ceramics there.

David Harrington Angus Douglas, 12th Marquess of Queensberry (born 19 December 1929) is an Anglo-Scottish aristocrat and pottery designer. He is the elder son of Francis Douglas, 11th Marquess of Queensberry, and his only son by his second wife, artist Cathleen Sabine Mann (married 1926 – divorced 1946). His maternal grandparents were an interior decorator, Dolly Mann (née Florence Sabine-Pasley) and artist Harrington Mann. He succeeded his father in 1954.

Queensberry has several siblings. By his father's first wife, he has an elder half-sister, Lady Patricia Douglas, whose daughter Countess Emma de Bendern was the first wife of gossip columnist Nigel Dempster. He has a late sister, Lady Jane Cory-Wright (1926–2007), twice married to David Arthur Cory-Wright, of the Cory-Wright baronets. He has a younger half-brother, Lord Gawain Douglas (born 1948), who is married with issue, one son and five daughters.