We are all used to talk of pensions deficits, and watching them see-saw up and down by several billion pounds every month in response to minute changes in gilt-yields has a way of diminishing their importance.

So what if the deficit is £90 billion this month? Next month it might be £150 billion, or it might be £40 billion. What's the use in worrying? We're going to pay this off over the very long term, after all.