"The unique continuity of the British parliamentary system has provided an unparalleled stage for political theatre over the past two hundred years. During the two centuries which separate the age of William Pitt from the age of Gordon Brown the conduct of politics has been transformed almost beyond recognition. The electorate has grown from a few thousand well-born men to include the entire adult population - forty-five million men and women at the last election. Debate that was once conducted in elaborately rhetorical speeches, often lasting several hours, in the chamber of the House of Commons is now concentrated into thirty-second soundbites on television, replayed infinitely on the internet. Governments come and go, parties rise and decline, the issues and ideologies which form the content of political controversy change over time - liberty or order; the prerogatives of the Crown or the House of Lords; tariffs or free trade; capitalism or socialism (or the particular balance between the two); above all, peace or war and the morality and cost of foreign interventions, whether in colonial America, continental Europe or the Middle East. Yet through all these changes of style and substance, the rivalry of ambitious individuals competing for the highest offices - the same offices, for the most part - has remained a constant, and the conduct of politicians merely adapts to different contexts. There is in every age a small number of dominating personalities who embody the contending philosophies of the moment; the clashing egos and human strengths and weaknesses of these key individuals shape the arguments and determine the historical outcome. These are the leaders who define their age."