Sinclair Alexander-Sinclair was born in Malta, the second son of Capt. John Hobhouse Inglis Alexander, of the Royal Navy, who served as aide-de-camp to Queen Victoria, and Isabella Barbara Hume, daughter of Thomas Cochrane Hume. He succeeded his elder brother in the Southbar property in 1892 and two years later adopted the additional name of Sinclair on succeeding to the estate of Freswick in Caithness. His paternal grandparents were Boyd Alexander, Lord of Southbar and Ballochmyle, and Sophia Elizabeth Hobhouse, daughter of Sir Benjamin Hobhouse, 1st Baronet and sister of John Hobhouse, 1st Baron Broughton. His father's elder brother was politician Sir Claud Alexander, 1st Baronet. He succeeded his elder brother in the Southbar property in 1892 and two years later adopted the additional name of Sinclair on succeeding to the estate of Freswick in Caithness.
Naval career
Alexander-Sinclair entered the Royal Navy as cadet in 1879 at the age of 14, becoming a midshipman 2½ years later. Edwyn Sinclair Alexander-Sinclair was first educated at Twyford School He was made lieutenant in 1890, and served as flag-lieutenant to both Admiral Tracey and Admiral Sir Michael Culme-Seymour, gaining promotion to commander in January 1901. He then had two sea commands, the destroyer from February 1902 serving at the Mediterranean Station from May that year; and after paying her off in January 1904, the despatch vessel until 1905. Alexander-Sinclair was promoted to captain in 1905, and was appointed commander of the Royal Naval College, Osborne, serving there until 1908, when he received the MVO. Between May 1911 and August 1913 he was captain of HMS Victory, the flagship of the Commander-in-Chief, Portsmouth. In 1914, at the start of World War I, Alexander-Sinclair was captain of the dreadnought, before flying his flag in from 1915 as commodore of the 1st Light Cruiser Squadron. He received the CB for his part in the destruction of Zeppelin L 7 on 4 May 1916. On 31 May 1916 it was the 1st Light Cruiser Squadron under Alexander-Sinclair that first engaged scouting vessels of the German High Seas Fleet and signalled "enemy in sight", leading to the Battle of Jutland, after which he received a Mention in Despatches from Vice-Admiral Sir David Beatty, commander of the Battlecruiser Fleet, and the Russian Order of St. Vladimir with swords. Promoted to rear admiral in 1917, he then commanded the 6th Light Cruiser Squadron, flying his flag in. In November 1918 Alexander-Sinclair was given the honour of leading the surrendered German Fleet into internment at Scapa Flow, and awarded the KCB. Soon afterwards, in December 1918, Alexander-Sinclair's 6th Squadron was sent to the Baltic, at the request of Estonian Government, to take part in the Estonian War of Independence. They delivered 6,500 rifles, 200 machine guns and two field guns. The British squadron also captured two Russian destroyers, Spartak and Avtroil, and turned them over to Estonia, which renamed them Vambola and Lennuk. Alexander-Sinclair then blockaded the Russian Navy base at Kronstadt until relieved by the 1st Light Cruiser Squadron under Rear-Admiral Walter Cowan. He was Admiral-Superintendent of Portsmouth Dockyard from 1920 to 1922, and then as a vice admiral, commanded the 1st Battle Squadron, Atlantic Fleet from 1922 to 1924, before serving as Commander-in-Chief, China Station from 1925 to 1926, and after promotion to admiral, as Commander-in-Chief, The Nore from 1927 to 1930. He retired in 1930.
