The British referendum on whether to stay in - or leave - the European Union may well be held this coming summer. It'll be a vote of momentous significance for Britain and for the EU. The polls suggest it could be a close-run thing. Stephen Sackur talks to Lord Lawson, president of the Conservatives for Britain group, which is campaigning for a British exit in defiance of prime minister David Cameron and his Conservative government's official strategy. The Eurosceptics have a historic opportunity - can they seize it?
