He retired as an Instructor Captain in the Royal Navy but was recalled to duty in 1941 to run the Bedford Japanese School, which trained young men and women for work at Bletchley Park.

In August Vice-Admiral Sir Gerard Noel, Commander-in-Chief of the China Station, wrote to Sir Claude Maxwell MacDonald, the first British ambassador to Japan, seeking the services of a ‘suitable and reliable Instructor in the Japanese language for service with the British China Squadron’, possibly a ‘suitable retired Japanese Naval Officer, who has perhaps been wounded in the war and would be glad of a little financial assistance’.

In February 1905, Macdonald replied to Noel to say that Baron Komura Jutarō, the Minister of Foreign Affairs, had been unable to find a suitable person.

Gubbins reported in September that Tuck had gained full marks in colloquial and more than 75% for each of the two written papers, and that he had a good knowledge of Chinese characters.

‘A little further study of newspapers, and a course of instruction in what is known as official dispatch style, would, I think, enable Mr. Tuck to attain the standard required for interpreters in the Japan Consular Service', he concluded.

[12] This indicates that Tuck was already well thought of in the Navy, and at the end of the year he decided to accept the appointment offered to him, and left Japan for the last time in his life.

[16] He continued to work on the volumes of the official naval history of the Great War until 1937, in the capacity of Technical Assistant in the Historical Section of the Committee of Imperial Defence.

[17] On the strength of his work as a historian, in 1934 he applied to the University of Cambridge when the position of Vere Harmsworth Professor of Imperial and Naval History fell vacant, but it was in the end offered to one of his referees, Admiral Sir Herbert Richmond (1871–1946).

[21] By October, after a spell at Weihaiwei, the Goliath returned to Yokoyama and Tuck applied for leave to remain in Japan for four months to learn Japanese.

Kikutake later graduated with a degree in Mongolian from Tokyo University of Foreign Studies and then worked on the South Manchurian Railway in Manchukuo, the Japanese puppet state in north China.

[26] He also played an active part in the Japan Society, which he joined as a life member in 1909: he served on the Council and gave lectures on a variety of subjects in the 1920s and 1930s.

[29] In fact, whereas most students studying scientific subjects or modern languages had already been called up for special war service, nobody had yet thought of a use for classicists, so Tiltman could take his pick of the best.

The few available dictionaries and textbooks all belonged to Tuck himself, and the course was devised by him in order to convey the essentials of the formal military Japanese that the students would later be handling.

Tuck was asked to write a history of the Bedford Japanese School, and on 7 December 1945 Frank Birch, the Deputy Director of the Government Code & Cypher School, wrote to acknowledge receipt of Tuck's account: ‘What you haven’t said in your history (but, thank goodness, it sticks out a mile) is your tremendous triumph over wrongheaded experts, red tape, neglect and almost impossible conditions.

Some became famous for other reasons, such as Denise Newman, who served as the only female skipper in the Royal Navy Auxiliary Service for eight years, and sailed single-handed across the Atlantic in 1988 at the age of 64, and Wilfrid Noyce, who was a member of the 1953 British Everest Expedition and later died in a mountaineering accident in the Pamirs.

[33] In 1946 Tuck was asked to take charge of a group of men who were required to translate captured Japanese materials at the Royal Naval College, Greenwich, and this lasted from 6 March to 22 November.

He was, however, warmly appreciated by his former pupils: Eric Ceadel continued to write to him from Cambridge, and David Goldberg, one of the many Jews at Bedford and Bletchley Park wrote, ‘I should like you to accept the little book enclosed herewith as a token of my thanks to you for the past six months so pleasantly spent in Bedford, and especially for helping me to keep our Jewish religious observances throughout the period.’ [35] A year after Tuck's death Ceadel, in a lecture at the Japan Society, wrote movingly of his memories of Tuck: 'The late Captain Oswald T. Tuck RN, who died early last year, meant much to me, for it was he who instructed me in Japanese.

Over 200 of his wartime students will always treasure a clear memory of his erect and dignified figure, with white hair and beard, and of his fine qualities of mind and character.