Mario Chanes de Armas, who has died in Miami at the age of 80, sailed from Mexico to Cuba in 1956 with Fidel Castro and Ernesto Che Guevara to launch the Cuban revolution. Two years after the revolution’s success, after criticising Castro’s lurch towards Moscow and communism, he was summarily jailed by his former comrade for 30 years.

Chanes de Armas served his full sentence, six years of it in solitary confinement in a windowless cell in which he could barely stand up, making him the longest-serving political prisoner in the western hemisphere at the time.