Faced with an illiteracy rate of more than 20% when they overthrew the Battista regime in 1959, the members of the new government set about trying to eradicate it altogether. On September 26 1960, Castro declared in the United Nations that “Cuba will be the first country in America that in a few months’ time will be able to say that it does not have a single illiterate person”.

The campaign, which caught the imagination of Cubans and has since achieved mythic status, mobilized 234,000 people of all ages, from students to pensioners, to go into the countryside and teach. The scale of the operation was obviously beyond the scope of the country’s existing 34,000 teaching workforce, but Castro determined to do it in a year. By day they worked alongside peasant farmers and fishermen and in the evenings instructed them in the rudiments of reading and writing. The symbol of the campaign was the kind of paraffin lantern used to light these basic literacy classes in village homes without electricity. China donated 100,000 of them to the cause. The story is told in evocative photographs at the National Museum of the Literacy Campaign - not, it must be said, yet on the Havana tourist trail. The student volunteers were typically aged only 14 to 16 when they set off - often with trepidation - on the campaign, which began on January 1 1961.

Some received death threats, and the Bay of Pigs invasion by Cuban exiles resulted in the deaths of 10 “martyrs”. For the aims of the campaign were avowedly political as well as educational.

Volunteers were equipped with two small booklets promoting the themes of the revolution, as well as a structured course and vocabulary. The first three vowel sounds introduced were O, E, A - initials of the Organizacion de Estados Americanos (Organisation of American States), from which, ironically, Cuba was soon to be expelled. Other sounds were identified with through words like Cuba, Fidel or Raul (his younger brother).

The “pupils’” final assignment was to write a letter to Castro and these have been lovingly collected at the museum, including the childlike scrawl of an 86-year-old man. He wasn’t the oldest though - she was 106 and her 14-year-old granddaughter was one of the teaching volunteers. Some said simply: “I am very proud to know how to read and write.” Another wrote: “I never felt Cuban until I learned to read and write.”