If all goes according to plan, the era of the Castros in Cuba will come to an orderly end in five years' time. Raul Castro, who took over from his brother Fidel in 2008, says he will step down from the presidency in 2018, and has nominated the young (ish) Miguel Diaz-Canel as his most likely successor.

The second President Castro has already done much to relax Cuba's communist rigour, loosening the constraints on private enterprise, for example, and abolishing hated travel restrictions. And in Sunday's speech, he outlined proposals for a two-term limit, and age cap, on the presidency. But he was keen to scotch suggestions of counter-revolution: "I was not chosen to be President to restore capitalism to Cuba."

Perhaps. But the fact that Mr Diaz-Canel is not one of the communist old guard creates a reasonable chance of more change after 2018 at least. Here's hoping.