Osborne de Vere Beauclerk, 12th Duke of St Albans (16 October 1874 – 2 March 1964) was a British peer and Army officer.
From his father's first marriage, he had an elder half-brother, Charles Beauclerk, 11th Duke of St Albans, who suffered from severe depression all his life.
[1] His father was the only son of William Beauclerk, 9th Duke of St Albans, and Elizabeth Catherine, daughter of Major General Joseph Gubbins.
He served with his regiment in South Africa during the Second Boer War, during which he was promoted to captain on 1 July 1901,[3] and returned to the United Kingdom in December 1901.
[7] At the outbreak of World War I, Captain Beauclerk was appointed aide-de-camp to Field Marshal Sir Douglas Haig, serving in France.