The Robert Mugabe school of economics provides a salutary warning about uncontrolled monetary expansion in generating hyper-inflation. The road to Harare is not as long as we might hope.

There was, of course, a global financial crisis. But our Labour predecessors left Britain exceptionally vulnerable and damaged: more personal debt than any other major economy; a dangerously inflated property bubble; and a bloated banking sector behaving as masters, not the servants of the people.

You can't win with some people. If you're not in government, you're criticised for being not serious. If you are in government, you're criticised for wanting power. That's the Labour party's line of attack, and it's a bit ridiculous.

My time at Shell was a most valuable experience because it taught me to look at the world in a long-term way. Shell takes a 20-year view on events and plans for different scenarios. It makes you see the world as a kind of large matrix.

Regulators are a backstop: they don't own banks. The governance at the top of our leading banks has been shown to be lamentably weak. No one at the top of Barclays will take responsibility for systemic abuse.

So I went into government with a clear mind about what the problems were, and what needed to be done.

The degree of leverage now being reversed is on a staggering scale, and the underlying global imbalances – notably between the savers and the spenders – will require long and painful adjustment.