One of the most powerful cultural myths of the English-speaking world over the past century has been the belief that if you work hard, you’ll earn enough to buy yourself a house and start a family.

For a long time, it held true. Between the end of the first world war and the turn of the millennium, rates of home ownership climbed rapidly in both Britain and the US, topping out at about 70 per cent as young adults flew the parental nest and set up homes of their own.

But in recent decades, that trend has not only stalled but reversed. In 1980, almost half of 18 to 34-year-olds in Britain and America lived in their own property with children of their own, making this the most common arrangement for young adults. Today that is true of only about one in five, and the most common set-up for 18 to 34-year-olds is now to be living with their parents.