On 3 October 1962, Hugh Gaitskell rose to address the annual Labour Party Conference in Brighton. He had been Labour leader for nearly a decade and was widely tipped to win the next general election, due within two years. Gaitskell’s message was clear and vivid: Britain must never join the European Economic Community. To do so, he told delegates, would ‘mean the end of a thousand years of history’.

While Gaitskell campaigned hard against a place in Europe, Prime Minister Harold Macmillan – ‘Supermac’ in political circles – was slowly melding a coalition of Conservative colleagues in favour of applying for EEC membership. As Macmillan saw it, the Conservative Party was split between romantics and realists. The romantics yearned for empire, quoting Churchill on an island standing alone. The realists, with Old Etonian Macmillan at their head, believed in some stark truths: Britain’s influence in the world was in sharp decline, its economy sluggish, its famed innovations in military hardware and pharmaceuticals long lost to the Americans. Without a European agreement, reasoned Macmillan, the slide would accelerate. While Britain languished, France and Germany were thriving amid unbroken growth and prosperity. Conservative pieties aside, Macmillan saw no viable alternative to a European alliance.