Alan Stripp added a new layer of mystery to his wartime career as a codebreaker when, in his late seventies, he recounted (in his one and only novel, The Code Snatch, 2001) a dramatic tale of subterfuge set in the final year of the war against Japan.

Late in 1944, when the action of his novel opens, Alan Stripp was based with the Army Intelligence Corps in India, reading Japanese radio traffic transmitted in a code that had long since been broken by the Allies. In the novel, he tells the story of how, when it was learnt from intercepted signals that the Japanese planned to change this long-established code for a new one, the Allies’ consternation led to a daring plan being hatched to snatch the only two volumes of the new codebook in existence.

How much of his plot is fact and how much fiction it is difficult now to say. Secrecy would obviously have surrounded any such activity at the time, and memories of that period were necessarily faint by the time Stripp’s novel appeared nearly 60 years later. All that the reticent Stripp would ever say in public was that his narrative was based on a true event, but when he started work on the novel he did reveal to his wife, for the first time, that this wartime episode had involved him being flown behind Japanese lines in Burma.

In essence, Stripp’s tale was that the Allies sent a bogus radio signal to a Japanese intelligence officer in Rangoon, pledging him to secrecy and ordering him to bring the two codebook volumes to an aeroplane that would land at Mingaladon airbase, where he was to hand them over to the “Japanese general” there.

The aeroplane, so Stripp’s story went, was a genuine Japanese aircraft captured by the Allies, the “general” was a Japanese-speaking Allied officer of Japanese origin, and, after much suspense, the Allied subterfuge was finally crowned with success. It is a story that could well have been adapted into one of the many war movies starring the late Jack Hawkins (whom Stripp somewhat resembled).

If the incident happened at all, was Stripp himself on the aeroplane to verify the codebooks as genuine? Or was his role merely to plant the bogus radio signal? This can only be speculated. What is certain is that, whatever his precise involvement, it is a plot rivalling that of Where Eagles Dare for audacity.

In spring 1943, when he was a first-year classics undergraduate at Cambridge, Alan Stripp was sounded out for an army career by an officer who, to Stripp’s surprise, quizzed him more about his interest in chess, crosswords and music than about any military inclination. As he later realised, these were factors that pointed to his suitability for a wartime career in codebreaking, and Stripp was being recruited for an intensive, six-month course in written Japanese that had been established the year before. The aim was to provide a pool of Britons with sufficient grasp of the written language to decode and read intercepted Japanese radio messages.

The course was no doddle. “Japanese is not just a difficult language,” Stripp wrote 46 years later in his first book, Codebreaker in the Far East. “It is totally different in form from most European languages and it suffers from being largely written in Chinese characters despite the difference between the languages.”

Over the next six months Stripp and his fellow students learnt about 1,200 of these Chinese-Japanese characters, poring over such faint reproductions, printed on yellowish wartime paper, that Stripp had to buy his first pair of spectacles.

At the end of training, Stripp was called up into the Army Intelligence Corps, and posted to the Government Code & Cypher School (GC&CS) at Bletchley Park,Buckinghamshire. There he translated signals sent, mostly from Burma, in the Japanese Army Air Force code known as 6633, which the enemy used over a wide area of their operations. This was a four-digit code, unusual in being based upon square substitution tables (Su Doku-like to the eye of the modern newspaper reader) consisting of 100 random digits.

Code 6633 had been almost entirely broken some months before Stripp’s arrival at GC&CS, and as a newcomer he was set to work translating signals that had already been decoded.

“I was dazzled by the picture which this one code painted of the Japanese military machine in action,” he wrote. “It was almost a shock to leave the building at the end of a long shift and emerge into the humdrum Midland landscape with not an Oriental face in sight.”

Five months later Stripp was posted to the Wireless Experimental Centre at Anand Parbat, just outside Delhi, where again he concentrated on radio traffic transmitted in Code 6633. Through decrypts, the Anand Parbat WEC was able to aid General Slim’s Fourteenth Army to detect and even predict the movement of enemy forces around Burma, and to Stripp it seemed likely that — during the closing stages of the war at any rate — the Allies had a clearer and more up-to-date picture of Japanese unit strengths and positions than did Imperial General Headquarters in Tokyo.

Following the Allies’ victory in Burma in May 1945, Stripp was posted to the Wireless Experimental Depot, a listening post at Abbottabad near Rawalpindi in India, where he had to learn Farsi to monitor Persian radio traffic. He was next assigned to decode Afghan traffic concerning anti-British guerrilla activity by the Faqir of Ipi, “a celebrated old rogue”, as Stripp leniently described him.

On being demobbed in 1946 Stripp resumed the life of a Cambridge undergraduate, later working for the British Council in Portugal and Java and as an administrator for Cambridge University’s Board of Extra Mural Studies, also lecturing on music. With his wife Mary, whom he married in Portugal in 1949, he helped to organise the music festival in the Cambridgeshire village where they lived.

In 1989 he published Codebreaker in the Far East, and in 1994 co-edited a second book, Codebreakers: The Inside Story of Bletchley Park, with another old GC&CS hand, Professor Sir Harry Hinsley.

His wife survives him. They had no children.

Alan Stripp, wartime codebreaker, was born on October 17, 1924. He died on February 18, 2009, aged 84