On pages 279-280 of the book Rajani Palme Dutt: A Study in British Stalinism by John Callaghan (Lawrence & Wishart 1993), the author writes the following:
“… the evidence points overwhelmingly to Dutt’s satisfaction with the Communist record. In preparing his book on The Internationale, for example, he had considered the inclusion of an anecdote to illustrate the ‘basic guilt of the accused’ [in the Moscow Trials]. Fortunately, although Dutt changed his mind about publication, this curious fragment survives and acquires an especially sinister light today in view of the fact that the Soviet state itself eventually admitted the falsity of the charges brought against the leading Bolsheviks in question. Dutt’s ‘evidence’ concerns ‘a lengthy day’s visit to the village at some distance from Moscow’ where Bukharin and Radek were at work in the summer of 1935. Here ‘under the seal of absolute secrecy’ they apparently ‘gave him a serious and alarming account… of the net in which they had become involved and of the dilemmas with which they were faced’. Dutt was told in very general terms, with no names mentioned, of how ‘opposition to the party, however much it might be felt to be justified at a given moment, can lead by its own logic step by step into the camp of counter-revolution’. He was accordingly advised to never enter this ‘fatal path of conflict with the party’ and retired with ‘the memory of this talk… like a nightmare’ weighing on his mind during the ensuing period. At first Dutt tried to convince himself that these old ‘friends and comrades’ had presented ‘an allegory to test him’ but he had ‘a lurking suspicion’ that their confessions of guilt were true and only failed to report them to the party by taking refuge in the ‘cowardly evasion’ that he had no grounds for certainty concerning their sins. Thus ‘when the trials followed, of Radek, and subsequently of Bukharin, it was as if a weight were lifted from the writer’s [Dutt’s] consciousness that, however terrible, the facts at last were out’. Dutt now read the trial statements of both men and as he did so ‘he felt as if he were reading the same story a second time, since their narrative corresponded so closely with what they had told him on that summer’s day and evening in 1935, even with many of the same phrases.'”
The source given is: Dutt, ‘Radek-Bukharin conversations ommitted from The Internationale’, 11 March 1964, CPGB archive.