Churchill, Attlee, Thatcher, Blair. Who were the great British political leaders of the 20th Century and what were the qualities that made them stand out? And is it true that today's politicians are minnows by comparison? Political diarist and former Labour minister Chris Mullin goes in search of greatness. Chris Mullin is the author of three widely acclaimed volumes of diaries and the novel A Very British Coup which was made into a successful television series.