At the age of 97, John Goodenough this week became the oldest person ever to win a Nobel Prize. The chemistry professor thereby settled an old score: 33 years before he won the award his employer, the University of Oxford, tried to make him retire before he wanted to. He “fled”, in his words, to Texas where he has spent the entire intervening period happily working — often at weekends.

Prof Goodenough’s work ethic demonstrates what is wrong with the oft-told story in rich countries about the young shouldering an ever greater burden as they support an ageing population. Those like the professor who might once have been pensioned off by their mid-sixties are now working longer themselves. The young, meanwhile, do not go off to earn as early as they once did, and spend far longer studying.

Social scientists have traditionally used a “dependency ratio” comparing the number of those between the ages of 15 and 64 to everyone else in order to assess the sustainability of welfare states. Those of “working age” must support those who cannot work. A high dependency ratio means fewer people are funding healthcare, education and social security programmes.