In early April 2010 Nick Clegg was fighting for recognition, the young, fresh and personable leader of Britain's third political party. Two weeks later he was the focus of 'Cleggmania' and his popularity was compared with Churchill's. Four weeks after that he became the second most important figure in the government - but within a year he was ridiculed and reviled as popular hopes turned to disappointment. But who is Nick Clegg? And by what route did he enjoy one of the most spectacular rises - and falls - in British politics?