Few Britons will have heard the phrase ‘apocalyptic winter’, but that may soon change. It’s how Italian politicians describe the season when deaths in the country outstrip births. In Italy, the total fertility rate (TFR), the average number of children born to a woman in her lifetime, is now 1.24, far below the 2.1 required to sustain population growth. Other European nations are faring worse: in Malta, it’s barely over 1; in Spain, just 1.19. In the........