Born in Auckland on 31 January 1912, Desmond Patrick Costello was the son of Dublin-born grocer Christopher Costello and his Australian wife, Mary Woods. An outstanding scholar, he attended Auckland Grammar School (1923–27) and Auckland University College (1928–31), graduating MA in 1932. That year he went to Trinity College, Cambridge, on a travelling scholarship, and eventually gained a first-class degree in the classical tripos. He was a brilliant linguist, fluent in French, German, Italian, Spanish and Greek, and would later learn Irish Gaelic, Russian and Farsi (Persian). He visited Germany in 1934 and India three years later.
Like many of his contemporaries, Costello joined the Communist Party of Great Britain while at Cambridge. Although he later claimed to have resigned his membership before the Second World War, he probably did so in 1940. The strength of his left-wing views remained a defining characteristic. On 6 September 1935, at Bethnal Green, he married London-born Bella (Bil) Lerner, a fellow communist whose Jewish family had Ukrainian origins; they would have five children. From 1936 Costello was an assistant lecturer in Classics at the University College of the South-West of England at Exeter. He was dismissed from this post in 1940, ostensibly because of an association with a student who had been convicted under the Official Secrets Act. Costello claimed that his anti-government views on foreign policy had prejudiced the university authorities against him.
He enlisted in the British section of the Second New Zealand Expeditionary Force in August 1940 and served with the 2nd Echelon in England until November, when he embarked for the Middle East with the rank of lance corporal. In March 1941 he was posted to the 21st Battalion and proceeded to Greece. He was promoted to sergeant just before the German onslaught led to the rapid evacuation of the Allied forces. When his battalion was dispersed at Pinios Gorge, he led members of its headquarters to the sea, where they escaped to Crete in a sailing boat.
This feat, and Costello’s proficiency in languages, led to his being sent to an officer training course in Egypt. Commissioned in September 1941, he served with the Long Range Desert Group before being appointed in February 1942 as a staff officer in Middle East Forces GHQ; his main task was to re-edit a handbook on the Italian forces. Three months later he was appointed the New Zealand Division’s intelligence officer, and he later became the general staff officer responsible for intelligence, serving until February 1944. Highly regarded by 2NZEF commander Lieutenant General Sir Bernard Freyberg, Costello was a strong personality who was conspicuous for his intellectual capacity, linguistic skills, enthusiasm for debate, singing talents and liveliness as a companion. His tendency to drink too much would occasionally get him into trouble, both during and after the war.
In July 1944 Paddy Costello (as he was now known) was discharged from 2NZEF to take up a diplomatic appointment at the newly established New Zealand Legation in Moscow. He had come to notice in Wellington for greeting in Russian visiting Soviet generals at Freyberg’s headquarters. His posting, as a second secretary, followed a meeting in London with Prime Minister Peter Fraser in May 1944. Although Costello did not hide his far-left beliefs – he is said to have told Fraser ‘I’m afraid I’m a bit left-wing, Sir’ – the prime minister was presumably unaware that Costello’s wife had, until April 1944 at least, been active in the British Communist Party.
Before proceeding to Moscow via Tehran in August 1944, Costello spent a few weeks at the Foreign Office in London, where he made an excellent impression. During his first months in the Soviet capital he concentrated on improving his Russian. In March 1945, temporarily restored to 2NZEF in the rank of major, he led a British military mission to Poland to deal with the repatriation of prisoners of war. During this 19-day expedition he visited the German concentration camp at Maidenek. In 1946 Costello spent 10 weeks as a member of the New Zealand delegation at the Paris Peace Conference. As rapporteur of a sub-committee, he played a significant and somewhat controversial role in the settlement of a Czech–Hungarian border issue. The outcome upset other Western delegates, but so pleased the Czechs that in 1947 they warmly welcomed him on a visit to their country.
Although at first disillusioned by what he found, Costello revelled in Russia and its cultural heritage. He travelled extensively and befriended Russian writers, including Boris Pasternak. As material conditions improved, his sympathy for the Soviet Union revived. This was evident in the perceptive reports he forwarded to Wellington on a range of issues, including social and political conditions and Soviet foreign policy. In 1948, in his spare time, he edited the second edition of Maurice Baring’s Oxford book of Russian verse , and the following year he prepared an annotated edition of a classic Russian play. He also wrote a satirical novel, which did not find a publisher.
Promoted to first secretary in 1947 and chargé d’affaires in July 1949, Costello was described by Secretary for External Affairs Alister McIntosh as ‘our most brilliant linguist and diplomatic officer’. He remained in Moscow until the legation was closed in June 1950. After briefly visiting New Zealand – the only time he did so after leaving as a 20-year-old, and a not entirely happy experience – he joined the staff of the New Zealand Legation in Paris in October. Increasingly dissatisfied with diplomatic life and conscious that his prospects of advancement were limited, he began to look towards an academic career. ‘I am really more interested in books than in diplomacy’, he told McIntosh in 1949. The issue assumed more importance in 1953 when Costello was put on notice that the government wanted him to find alternative employment. Eventually, at the insistence of Prime Minister Sidney Holland, his resignation was obtained by McIntosh in July 1954. His employment ceased on 30 September, though he was paid until 2 January 1955.
British concerns about Costello’s loyalty lay behind this. His role came under renewed scrutiny in 1961, when the infamous Soviet spies Morris and Lona Cohen were found to have New Zealand passports (under the name Kroger) issued by the Paris legation in 1954. The assumption of Costello’s involvement was misplaced, for there is nothing to connect him directly with the Cohens; nor would his intervention have been necessary to secure the passports. Nevertheless, in later years public speculation that Costello was a Soviet agent was regularly fuelled by the supposed revelations of various Soviet defectors or agents. In 1999 evidence purporting to come from Soviet archives seemed to reinforce the allegations, indicating that he had operated as a Soviet agent in Paris under the code name ‘Long’. Since he was never charged with any offence, and no official acknowledgement of his activities has been (or is likely to be) made, confirmation of such claims must await scrutiny of records presumably still held in Moscow.
Costello’s hopes of securing a position with UNESCO or the United Nations Technical Assistance Board, perhaps in Afghanistan, came to nothing. Instead, he returned to his first love, scholarship, being appointed to the chair of Russian studies at Victoria University of Manchester. Taking up the post in October 1955, he revitalised the department and won the admiration of colleagues and students. He died of a heart attack in Manchester on 23 February 1964, survived by his wife and children.