He was also the author of a two-volume Short History of the Russian Revolution (1937). In the book he attempted to justify the Great Purge: "The Fascist Powers were able to use a number of Trotskyists, some of whom, like Trotsky, resided abroad, while others were in the Soviet Union. These men proved willing to turn traitor to their country and to the cause of Socialism. In December 1934 one of the groups carried through the assassination of Sergei Mironovich Kirov, a member of the Political Bureau of the Central Committee of the Communist Party. Subsequent investigations revealed that behind the first group of assassins was a second group, an Organisation of Trotskyists headed by Zinoviev and Kamenev."

Arnot's next book was Fascist Agents Exposed in the Moscow Trials (1938). 

Robert "Robin" Page Arnot (15 December 1890 – 18 May 1986), best known as R. Page Arnot, was a British Communist journalist and politician.