Krug makes an average of only 450,000 bottles a year – well under one per cent of the world’s champagne – but it is often described as the Rolls-Royce of the industry. Its devotees, who have called themselves “Krugists”, include Ernest Hemingway, John le Carré, Sir Alec Guinness, Naomi Campbell and the late Queen Elizabeth the Queen Mother, who used to sneak in bottles whenever she was in hospital. Their biggest market is Japan, followed by the US and Europe, and they will soon be shipping bottles to Nigeria, where the president’s wife is a fan.