Late in 1944, Milner was appointed to the Post-Hostilities Division (P-HD) of the Australian Government's then Department of External Affairs. In 1945, Milner allegedly stole a number of classified documents and passed copies of the documents to the Soviet embassy through an agent code-named KLOD, who was a key organiser of the Soviet Union's intelligence gathering activities in Australia and who was believed to be Walter Seddon Clayton.5
Declassified Venona reports, including intercepted cable traffic from the Soviet embassy in Canberra to Moscow, show that Milner regularly passed classified British post-war strategic planning documents to the Soviets between 1945 and 1946.6
From 1947 to 1949, Milner worked in New York with the Australian contingent in the Political Office of the United Nations Security Council. His work covered problems in the Balkan states, Middle East, and Korea. Milner appears to have actively continued to work with Soviet intelligence while posted to New York. He and his wife held deeply anti-American views and the United States Government is believed to have opened a security file on him.7
One of Milner's colleagues from the Department of External Affairs, Jim Hill, was transferred to London in June 1950. Hill and Milner are said to have had similar sympathetic views of the Soviet Union. Shortly after arrival, Hill, code-named TOURIST, was interrogated by MI5 on suspicion of being a Soviet agent. Hill was not charged with treason, but was moved to a role that no longer provided access to sensitive information. It is likely that Milner was warned of Hill's interrogation by his Soviet handlers during a short holiday to Switzerland in June 1950. Milner defected to Czechoslovakia in July 1950 where he became an English teacher at Charles University in Prague.8
From Prague, Milner denied ever being member of the Communist Party of Australia or wittingly divulging confidential information to any unauthorised person.9
As a pro-communist New Zealander living behind the Iron Curtain, Ian Milner was a uniquely placed witness of the 1968 Prague Spring. He was enthusiastic about the reforms of Alexander Dubček. His letters give insight into the dream of many Czechoslovak communists for a type of communism that would not be Soviet-dominated.10
The Rhodes Scholar Spy (Random House Australia, 1991) by Richard Hall ↩
Ball, Desmond (16 April 2011). "The moles at the very heart of government". The Australian. http://www.theaustralian.com.au/national-affairs/the-moles-at-the-very-heart-of-government/story-fn59niix-1226039586701 ↩
Intersecting Lines, the Memoirs of Ian Milner (Victoria University Press, 1993) edited and introduced by Vincent O'Sullivan /wiki/Vincent_O%27Sullivan_(New_Zealand_poet) ↩
Dance of the Peacocks, New Zealanders in exile in the time of Hitler and Mao Tse Tung (Random House, 2003) James McNeish /wiki/James_McNeish ↩
Encyclopaedia of Cold War Espionage, Spies, and Secret Operations (Enigma Books, 2013) by Richard C.S. Trahair ↩
Ball, Desmond (28 May 2011). "Turning a blind eye to espionage". The Australian. http://www.theaustralian.com.au/national-affairs/opinion/turning-a-blind-eye-to-espionage/story-e6frgd0x-1226063991348 ↩
Jackson, Aaron (Oct 2021) "Socialism Tells its Own Story: Ian Milner and the Dream of a Redeemed Socialism in the Prague Spring" New Zealand Journal of History https://muse.jhu.edu/article/836313/pdf ↩