But if Mr Brown is the favourite son, Mr Blair, despite being younger, enjoys a more avuncular role, exploiting his slight distance from the party to tease it, lecture it, and tell it one or two home truths.

ECONOMIST: Browned off with Blair?

In his recent Keir Hardie lecture (named after Labour's first leader) David Miliband evoked his party's pre-war tradition of mutual guilds and moral seriousness, rather than the mix of Fabian statism and cultural relativism that has prevailed since.

ECONOMIST: Bagehot

On Saturday, Mr Clegg will be paying homage to the left of his party, the social democratic group Social Liberal Forum, when he delivers the annual Beveridge lecture on the "five giant evils" - squalor, ignorance, want, idleness and disease.

BBC: A tough end to a tough week for Nick Clegg