[5] He graduated with a first-class honours degree in law from Victoria University College in Wellington where he had been an excellent sportsman in track athletics, boxing and as a rower.
Mills was a friend of Olympic gold medallist and anti-fascist Lewis Clive, who died fighting against Nationalist forces in 1938 during the Spanish Civil War.
According to Platts-Mills' own account, Sir Stafford Cripps introduced him to prime minister Winston Churchill, who told him: "I have been teaching the British since 1918 that the Russians eat their young.
"[12] In 1948 Platts-Mills ceased to be a Labour MP, after an episode of factional strife, in which he was responsible for a telegram of support sent to the Italian socialist leader Pietro Nenni in April of that year.
Platts-Mills sent off the telegram, with Hyman Berger who was now his parliamentary clerical assistant, on the evening of 16 April, despite a warning earlier that day from Geoffrey Bing of potential trouble with the Labour whips.
[1][17] According to Platts-Mills, Labour had in 1944 recognised the continuity of Nenni's party with the pre-Mussolini Italian socialists;[18] and the endorsement was repudiated after the telegram was sent by Hector McNeil and Morgan Phillips, in favour of Saragat's group.
[19] Edmond writes the telegram was provocative and the furore predictable, that the switch to support for Saragat was under consideration at the time, and that Ernest Bevin came under pressure from George Marshall to expel Platts-Mills, a critic of American foreign policy.
[1] The expulsion of Platts-Mills led to the formation in 1949 of the Labour Independent Group which gained support from four other Soviet-sympathising ex-Labour MPs: Konni Zilliacus, D. N. Pritt, Geoffrey Bing and William Warbey.
[2] "A master of courtroom theatre.. [whose] clashes with the Bench entered into legal legend",[2] Platts-Mills was defence counsel to many clients, including the Great Train Robbers at their appeal[1] and Ronnie Kray.
[21] Platts-Mills was said to have encouraged Billy Strachan, a fellow communist activist and one of the pioneers of black civil rights in Britain, to study law.