That Britain's Conservative Party is deeply sceptical about the European Union isn't news. What is novel is the readiness of some of the party's grandest grandees to call for a British exit. Stephen Sackur talks to Lord Lawson, Margaret Thatcher's former Chancellor, who recently labelled the EU a bureaucratic monstrosity, past its sell-by-date. His intervention embarrassed prime minister David Cameron and deepened the impression of a Tory party dangerously divided. So, why did he do it?