After almost half a century at the helm, Fidel Castro has decided it is time to step off the rostrum, take off his fatigues and slow down. True, the ageing revolutionary has not been seen around for a while: since a stomach operation 18 months ago, he has appeared only fleetingly on television and has barely uttered a word in public. To Cubans missing his marathon eight-hour harangues he has now sent a letter, suggesting that he will not be returning to office but will advise the Government as an “elder statesman”.

It may be hard to imagine anyone elder than Castro, but a lifetime of fine cigars, bad Marxism, strong rum and the occasional CIA assassination attempt have clearly taken a toll. He looks gaunt; the revolutionary fires are now a mere flicker of the blazing eyes and guns that chased Fulgencio Batista from Havana in 1959.

How very different from our own dear Queen, who, at 82, is a few months older but is still dubbing knights, unveiling plaques, opening Commonwealth conference, entertaining Saudi monarchs and inviting Arsenal players to tea. On Saturday she becomes the oldest monarch to sit on the throne. Whether it is her, or the nation’s, robust constitution, the House of Windsor has found an elixir that she might pass on to the greybeard of Havana. For exercise, he should try eightsome reels, riding sidesaddle, deer stalking and walkabouts through shopping centres. He should avoid spicy foods, sharpen his small talk and busy himself with small dogs. Instead of Communists, he should hobnob with bloodstock owners. He should limit his speeches to Christmas broadcasts. Above all, he should smile.