I was walking with my 23-year-old daughter on London’s South Bank the other day when she asked me whether I had ever lived in a “golden age.” I immediately recalled the 1960s, when all the world (and I) was young and full of vivid colours and beautiful people.

But then I remembered my studies as an economics undergraduate in the 1960s. These were dominated by the travails of the British economy: big balance of payments deficits, sterling crises, GDP per head below that of most countries in western Europe and falling back on most social indicators too. A little later, when I’d completed my studies and was attending conferences abroad as a jobbing economist, I always found myself apologising for Britain, and trying to explain what had gone wrong.

My daughter was waiting for an answer. I looked around. We were standing by the Globe, near Tate Modern, looking over