This is the story of the most signifi cant new British political party in a generation. New parties are founded all the time, but most are tiny clusters of discontents bound together by a single, marginal issue. Most wither and die very quickly. Others, like the nationalists in Scotland and Wales, have changed the face of politics in their nations, but by its nature their appeal is geographically limited; they could not change the balance of power in Britain as a whole, nor did they aim to do so. This has left the commanding heights of British politics dominated by only three political parties – the Conservatives, the Labour Party and the Liberal Democrats – whose electoral ancestors started taking seats at Westminster a century or more ago. Their individual fortunes may have ebbed and fl owed from one election to the next, but together they have reigned supreme. Only once in that time has a new force emerged with suffi cient support across the whole of Britain to challenge their monopoly on political power, although even this was not a genuine grassroots insurgency.