EDINBURGH, SCOTLAND - SEPTEMBER 10: Craig Oliver, Director of Communications for the Prime Minister lookson as David Cameron speaks during a visit to Scottish Widows offices in Edinburgh, where he made an impassioned plea to keep Scotland part of the union, saying he would be "heartbroken" if the UK was torn apart on September 10, 2014 in Edinburgh, Scotland. The three UK party leaders are all campaigning in Scotland today showing their support for a "No" vote in the independence referendum. (Photo by James Glossop - WPA Pool /Getty Images)
