Over the last decade, - economists seemed to share a broad consensus about economic policy, with the old splits between monetarists and Keynesians apparently being settled by events. But the Great Recession of the last two years has changed everything.

Inflation is not always the main problem, or indeed a problem at all. Sometimes, though rarely, deflation is a more serious threat, and we need to shelve many of the orthodoxies we have held so dear.

There is an honourable tradition in British public life that those charged with authority at the top of an organisation should accept responsibility for what happens in that organisation. I am therefore writing to the prime minister today to tender my resignation as chairman of the BBC.

As long as the appointment process is transparent and there is a broad mix of political views among the governors of the BBC, I think the public can feel confident that impartiality and independence are just as important to me as they have been to previous incumbents.

The BBC should not have a cheerleader. It should have somebody who runs the organisation in the interests of the public and that should be a chairman.

The BBC must never be all about ratings - or even mainly about ratings. In the past year, we have made a raft of terrific programmes which stand comparison with the best the BBC has ever done: 'Blue Planet,' 'Walking with Beasts,' 'Son of God,' 'Clocking Off,' 'The Way We Live Now,' 'Conspiracy,' 'Lost World.

The BBC provides the commentary on our lives, the soundtrack of the nation. It is one of the most powerful unifying forces in the United Kingdom today.