In October 1963, Sir Herbert Stanley Marchant, the outgoing British ambassador to Cuba, sent the Foreign Office a six-page confidential profile of Fidel Castro, now held in the National Archives at Kew. Marchant joked that if it didn’t fit the Foreign Office’s purposes he would sell it to Life magazine when he retired, to keep himself ‘in beer money for a month or so’. He had been ambassador since 1960. For most of that time, he writes, Castro had had ‘nothing whatever to do with Western diplomats’, but the policy changed suddenly after he returned from a trip to the Soviet Union in 1963. Marchant had since spent eleven hours with Castro at close quarters, including ‘two lunches and a farewell interview’.

The ambassador couldn’t help but be impressed by Castro’s presence: ‘However much you hear about the Grand Canyon it still turns out to be much bigger than you expected. So it is with Castro – and I do not mean merely his physique. He is in fact a good six feet four inches and he must weigh sixteen stone.’ Whether in ‘small private groups or large public gatherings’, Castro ‘takes the centre of the stage with a natural assurance far beyond that of any other prima donna I have ever met’. He ‘has charm in plenty and is more than usually attractive to women in all spheres of life. I have seen wives and daughters of Western diplomats cluster around him like school girls round their gym mistress.’ (Marchant’s similes betray an oddly narrow frame of reference, unless it was for the benefit of his Foreign Office colleagues in London.)

Marchant puts much of Castro’s behaviour down to his supposed ‘megalomania’, but observes that ‘he curiously enough chooses a crusade for other people as the setting in which to exhibit himself. He is a natural “do-gooder” and he fancies himself as such.’ Marchant patronisingly imagines that Castro ‘has Walter Mitty-Like dreams of himself in shining armour, mounted on a white horse leading the poor and oppressed of Latin America to freedom and prosperity’. Yet the ambassador also concedes that ‘a genuine passion for the poor and under-privileged is definitely built into his make-up and the warmth of affection he professes for the Cuban peasant is almost certainly genuine.’

Castro’s heart is said to bleed easily, ‘especially of course for victims of Batista corruption and “Yankee Imperialism”’, but even in his dealings with counter-revolutionaries, Marchant says, he prefers ‘the magnanimous gesture of granting pardon to giving the order to shoot’. Castro assured the ambassador that ‘the policy of his regime was strictly humanitarian and that it prided itself on the fact that not even its worse enemies had been tortured or otherwise treated with brutality in prison.’ Marchant reluctantly acknowledges that this was ‘probably basically true’. He also says that he has seen no signs to justify ‘counter-revolutionary stories of gluttony or drunkenness’. On the contrary, Castro’s lifestyle was ‘essentially bohemian’ with ‘no luxury, no veniality’.

Castro told Marchant that he spear-fished at a depth of 40 to 60 feet without breathing apparatus, which suggested ‘a remarkably sound body and first class lungs’. He was ‘a little paunchy beneath his broad, slightly rounded shoulders’ (counter-revolutionaries claimed he was wearing a bulletproof vest) and needed glasses to play baseball, but Castro – then 37 years old – still stood out ‘as an impressive physical specimen, especially in comparison with his brother Raul, the unattractive runt of the family’.

Fidel wasn’t ‘a profound or original thinker’, Marchant says, and would ‘have got a good Second rather than a First Class at Oxbridge’. But he ‘can think clearly and quickly and can argue with a lawyer’s shrewdness’. As for ‘the character of the man and the standard of values by which he lives’, Castro was neither ‘all black’ as counter-revolutionaries argued, nor a ‘Sir Galahad as his followers would have us believe’. Even his enemies would concede that he had ‘guts’ and displayed ‘courage in the face of physical dangers’.

Leading Personalities in Cuba, an official British Embassy intelligence report, was written in the same year as Marchant’s profile. It contains concise descriptions of the seventy most prominent political figures in Cuba. The entry for Castro is reminiscent of Marchant’s longer study, but less nuanced: his ‘gigantic ego and emotionally undisciplined nature is not of the stuff of which good Marxists are made’. It also says that he ‘has a better knowledge of English than he normally admits’ – as he’d revealed in an interview on US television in 1959.

The entry for Che Guevara, then the minister of industry, is more positive. It calls him ‘the most practical and probably the clearest-headed of the inner circle … extremely able and hardworking but prefers to stay in the background’. ‘Cultured and soft spoken when he likes to be … this aloof and bearded character exercised considerable fascination over men and women around him.’ As industry minister, he is praised for his ‘forceful, practical but revolutionary approach to the problems in hand. He is frank and outspoken in his criticisms of administrative muddle and inefficiency.’ The entry concludes that Guevara was ‘probably second only to Fidel Castro in the hierarchy of power’.

Fidel’s official deputy was his brother Raul, who’s described as a ‘most unpleasant young man’ and, once again, the ‘runt of the family’, with ‘extremely Left-wing views’. The entry speculates that ‘it is very doubtful whether he has the calibre or personality to remain long in Fidel’s saddle, should it become vacant.’ Raul Castro succeeded his brother in 2008. More than fifty years after British intelligence made its dismissive assessment of him, the Cuban Revolution remains in power with Raul at its head.