In the nineties and parts of the noughties, investors fell in the habit of talking about a Goldilocks economy, which combined moderate economic growth with low inflation. The economy was neither too hot, nor too cold: it was just right.

No one thought what would happen when Goldilocks ate too much of the lashings of tasty porridge served up by bankers, as a result of her willingness to take risks with her health. But the result was inevitable: indigestion.