Sir Reginald was born in Marylebone, Westminster, the younger son of John Plunkett, 17th Baron of Dunsany (1853–1899)[1] and his wife, Ernle Elizabeth Louisa Maria Grosvenor Burton, later Plunkett-Ernle-Erle-Drax (1855–1916).

[5] She died in 1916, leaving Reginald the majority of her vast estates in Dorset, Kent, Surrey, Wiltshire, Yorkshire, and the West Indies.

[6] His long series of titles, Christian names, surnames and post-nominals has made him famous beyond his career as an admiral in the Royal Navy.

[9] The Times obituary claimed that Drax's book was dismissed by the skeptical older generation of admirals, who thought it highly presumptuous for a lowly lieutenant to write with authority on naval tactics.

[4] He served during the First World War aboard the battlecruiser HMS Lion[1] and was present at the naval battles of Heligoland Bight, Dogger Bank and Jutland.

[1] In a 1929 memo, he argued that there were three aspects to a naval battle, namely "geometry" (the movements of ships), "tactics" (the use of weapons to sink the enemy warships) and "morale" (the spirt of the crew).

[10] Drax argued that morale was the most important of his trio, and to win a battle required aggressive officers prepared to take risks by engaging the enemy fleet head-on and close-in.

Backhouse felt that the increasing aggressive Japanese behavior as demonstrated by the Second Sino-Japanese War made it imperative to finally work out how to best implement the Singapore strategy.

[12] A memo stated: "Drax favored relying on small, mobile forces to deter the Japanese from interfering and overrunning British interests in the Far East.

[12] Drax admitted that his plan would require the British to stay on the defensive on the account of the numerical superiority of the Japanese Navy and it would be impossible to deliver a "knock-out blow" against Japan with the forces envisioned.

[13] Drax argued that Britain needed control of the Mediterranean Sea both to supply and reinforce the forces in Singapore and to allow the necessary numbers to take on Japan.

[14] He was the British half of the Anglo-French delegation sent to Moscow in August 1939 alongside General Joseph Doumenc to discuss a possible alliance with the USSR with Soviet Defense Commissar Kliment Voroshilov.

[1] As an indication of the low priority the Allied governments put on the mission, it was sent by sea aboard the outdated merchant ship City of Exeter on a slow voyage to Leningrad.

[15] The Soviet ambassador Ivan Maisky, confronted Drax about the choice of transportation, asking him why he was travelling on the City of Exeter instead of taking the first flight to Moscow.

Furthermore, although the Allied governments were willing to grant the Red Army transit rights through Poland and Romania they were unwilling to allow them to enter Polish Galicia and the Vilno Gap.

The British government also ignored advice to send an officer of equivalent rank as Edmund Ironside, who had been sent on a similar mission to meet Polish Marshal Edward Rydz-Śmigły in Warsaw.

[1] Alongside Admiral Herbert Richmond and Vice-Admiral Kenneth Dewar, Drax was considered to be an intellectual with controversial views, including the need for naval reform.

[1] His friend, James Bond novelist Ian Fleming, named the character Sir Hugo Drax in his book Moonraker as a tribute.