The weekly punch-up that takes place at Westminster every Wednesday, otherwise known as prime minister's questions (PMQs), is not the place you would normally look for enlightenment. But last week it provided an instructive exchange on two different approaches to leadership.

The context for this exchange was the ongoing row over the dubious expenses claims made by some members of the UK parliament. David Cameron, leader of the Conservative party, set out his views in clear terms. “Is it not time to stop the talking and the endless committees, and start showing some real leadership to deliver some real change?”, he asked.

Prime minister Gordon Brown explained how he planned to proceed. “On all these issues, I am trying to build a political consensus on change . . . Leadership is about the whole of the political system responding to the changes that need to be made.”