The United Kingdom’s relationship with the European Union has long been fraught, creating tensions with European partners and dividing the main political parties. To try to overcome internal divisions in the Labour Party, Harold Wilson sought to renegotiate the UK’s terms of membership and then held a referendum on whether the country should stay in. The result – a two to one majority of remaining - was thought to have ended the question marks over British membership definitively. Four decades later, it was the Conservatives who were divided over Europe and Prime Minister David Cameron, in what appeared to be almost a carbon copy of Wilson’s actions, promising reform, renegotiation and a referendum. Yet the stakes in 2016 were rather higher than in 1975 and the challenges far greater - the more multi-faceted and institutionalised nature of the EU rendered the debate, and the potential costs and benefits, more complex. This article assesses the similarities between the two prime ministers’ decisions to renegotiate the UK’s terms of membership and the frameworks established for the ensuing referendums and notes significant differences, which render over-interpreting the parallels a risky business.