text: Lady Mairi Elizabeth Vane-Tempest-Stewart (1921–2009), who married in 1940 (div. 1958) Derek William Charles Keppel, Viscount Bury (1911–1968), eldest son of Walter Keppel, 9th Earl of Albemarle and had issue: (i) Lady Elizabeth Mairi Keppel (1941–2014) who married in 1962 (div.) Alastair Michael Hyde Villiers (1939–2005) and has issue, and in 1980 (div. 1988) Merlin Hanbury-Tracy, 7th Baron Sudeley; and (ii) Lady Rose Deirdre Margaret Keppel (b. 1943) who married Peter Lathrop Lauritzen, son of George F. Lauritzen, of River Forest, Illinois, U.S.A., founder of a food manufacturing, processing and export firm, and has issue.
  Lord Londonderry had an illegitimate daughter with actress Fannie Ward, named Dorothé Mabel Lewis (b. 1900). She first married, in 1918, a nephew of mining magnate Barney Barnato, Capt. Jack Barnato, who died of pneumonia shortly after their wedding. Her second husband, whom she married in 1922, was Terence Plunket, 6th Baron Plunket, and with him, she had three sons: Patrick Plunket, 7th Baron Plunket, Robin Plunket, 8th Baron Plunket, and the Hon Shaun Plunket. Lord and Lady Plunket were killed in an aircraft crash in California in 1938.
  Having suffered a stroke after a gliding accident a few years after the end of the war, Lord Londonderry died on 10 February 1949 at Mount Stewart, County Down, aged 70.