The government, seeing culture as promoting national prestige, facilitates this. The dancers give part of their foreign earnings to the government – but then our own dancers pay income tax too.As a profession, dancers are perhaps more fortunate than others in Cuba. At least they are likely to find work, teaching or performing. Besides the National Ballet, there are classical, modern and folk dance companies And there are ballet schools in many of Cuba’s provinces. The National school, housed in one of Havana’s many elegant, palatial buildings, is being extensively refurbished.

Castro’s gala speech stated an aim to place 400 students in the refurbished school and to increase the number of provincial schools. The best will become professional performers, others will become teachers, and the rest an educated audience.Among the society at large, though, things seem less clear-cut. Talk to one Cuban and he still believes in the Revolution; talk to another and you find disillusion. The hotel porter who trained as a pilot for two years in Russia and speaks several languages returned to Cuba to find there were no jobs for his training He is on an island prison because he can’t leave.

It is the ultimate sacrifice, where the individual is subordinated to the collective.Nobody knows what will happen to the Caribbean island when Castro dies. But when Alonso dies, she will leave a wonderful training system and extensive provision for this, but a repertory as troubled as the Cuban economy.Carlos Acosta leads Havana’s Danza Contemporanea in his first full-evening choreography, at Sadler’s Wells Theatre, London EC1 (020-7863 8000), 15-26 July. There is a certain genre of American science writing that prides itself in checking facts. So much so, indeed, that professional fact-checking is part and parcel of the editing process. Robert Preston, who uses facts like a builder uses bricks, is gracious enough to acknowledge his own fact-checker, who no doubt had his work cut out with The Demon in the Freezer. Such a production facility would have broken just about every rule in the biological weapons book.After smallpox was eradicated in the wild in the 1970s following a worldwide vaccination campaign, the World Health Organisation co-ordinated the collection or destruction of laboratory stocks. Only two places were officially allowed to retain live smallpox.