Beyond Westminster - What makes a good political leader?

As Nick Clegg tries to reassure his party, and as Labour is poised for a new supremo, what is the essence of good political leadership? Beyond the debate about policy specifics, what human qualities are essential? Can these be taught or learned over time or do some individuals just have them while others never will? Is luck essential or can adversity be the best way to improve leadership skills? Is what's required changing or is it timeless? And are all our political leaders becoming more similar, all formed in the same Westminister bubble? John Kampfner talks to those who've been at the political sharp end, and quizzes leadership experts on whether they could make a political difference. Political biographers will add their thoughts on the key moments and characters in leadership past and present. Producer: Chris Bowlby.