1. Reginald Tyrwhitt led a supporting naval force of 31 destroyers and two cruisers at the Battle of Heligoland Bight in August 1914, in which action the 1st Battlecruiser Squadron under Sir David Beatty sank three German cruisers and one German destroyer with minimal loss of allied warships.
Tyrwhitt led the British naval forces during the Cuxhaven Raid in December 1914, and at the Battle of Dogger Bank in January 1915, in which action Tyrwhitt again supported Beatty's powerful battlecruiser squadron.
Reginald Tyrwhitt served as Commander-in-Chief, China during a period of disturbances and tension with the Nationalist Government.
Reginald Tyrwhitt became commodore of all destroyers in the First Fleet in December 1913.
Reginald Tyrwhitt led the British naval forces during the Cuxhaven Raid in December 1914, when British seaplanes destroyed German Zeppelin airships, and at the Battle of Dogger Bank in January 1915, in which action Reginald Tyrwhitt again supported Beatty's powerful battlecruiser squadron.
Reginald Tyrwhitt was awarded the Distinguished Service Order on 3 June 1916, appointed a Commander of the French Legion of Honour on 15 September, and made a naval aide-de-camp to the King on 21 May 1917.
Reginald Tyrwhitt was advanced to Knight Commander of the Order of the Bath on 15 July 1917, and appointed an Officer of the Military Order of Savoy on 11 August.
Reginald Tyrwhitt took part in the Zeebrugge Raid and the Ostend Raid on the night of 23 April 1918, for which he was awarded the French Croix de Guerre on 23 July.
Reginald Tyrwhitt was promoted to rear admiral on 2 December 1919, and created a baronet of Terschelling and of Oxford on 13 December.
Reginald Tyrwhitt was appointed First and Principal Naval Aide-de-Camp on 10 October 1932.
When he hauled down his flag for the last time in May 1933, Reginald Tyrwhitt was the last British flag officer who had served in the First World War to do so.
Reginald Tyrwhitt died at Ellenden Nursing Home in Sandhurst, Kent on 30 May 1951.
In 1903 Reginald Tyrwhitt married Angela Corbally; they had two daughters and a son.