After several years of successfully bottling the Conservative Eurosceptic Genie it has been released again: a draft bill offering a yes-no vote on EU membership is promised and two Cabinet ministers, Michael Gove and Philip Hammond, have declared they favour withdrawal.

Such referendum promises have been made before and the demands for one have a long pedigree. With the 1961–63 EEC entry negotiations Party activists sought reassurances of a referendum. Harold Macmillan gave none, nor would Edward Heath a decade later, despite the Party’s own polling showing in 1970 that six out of ten Conservative voters wanted such an option. Labour conceded a referendum in 1975 in order to hold its unity and a two to one vote said yes to Europe. Referendum demands re-emerged in the late 1980s and especially during the protracted Maastricht parliamentary process of 1991–93. John Major's leadership challenger in 1995, John Redwood, was partially standing on the referendum ticket. Then in the run-up to 1997 Mr Major became 'minded' to hold a referendum on the single currency.

The emergence of explicitly anti-EU parties (both the Referendum Party and UKIP) has meant Conservatives keeping a watchful eye for signs of a Eurosceptic electoral takeoff. William Hague's answer was to allow his party to vote whether a future government would accept the single currency: 84% said no. But the 2001 election showed what the electorate thought of a single-issue Conservative party.

For all the current bluster, there is, historically speaking, little evidence that sounding Eurosceptic is a vote winner. It carries low voter saliency and they care more for economic competency. Maybe Conservatives are looking to Margaret Thatcher's battles over the European budgetary rebate, which she used to distract from her own unpopularity, recession and record unemployment figures. There will certainly be some siren voices in Conservative HQ telling Mr Cameron that he needs to steal UKIP's thunder and shore up the core Conservative vote.

But if history is any guide, it is exceedingly unlikely that this referendum pledge will ever be fulfilled. For one thing, the bill needs to be enacted. Then the Conservatives need to win the 2015 election, and it is far from clear that promises of a referendum will greatly aid that cause. The last time the Conservative's pledged themselves to a referendum, in the run-up to the 2004 European elections, Tony Blair neutralised the threat with a similar pledge – but did the country ever see that referendum?

Given the need to dent Mr Miliband's lead in the polls, the current furore might be animated by a hope that it will force into public view Labour's own divisions – Labour for a Referendum has launched, and, contrary to popular opinion, Europe has historically been a far more toxic issue for Labour than for the Tories: witness the 1983 pledge to leave the EU, the earlier split that led to the formation of the SDP, and the deep divisions over entry and renegotiation in the 1970s.

Finally, why has Mr Gove broken cover? Leadership ambitions are never far from the surface for the Tories and we are currently witnessing the latest installment, as candidates jockey for who will succeed Mr Cameron should electoral failure occur in 2015. Mr Gove would do well to look to history and remember two things: first, that he who wields the knife rarely wears the crown (as Mr Heseltine discovered to his cost in 1990); and second, that previously successful Eurosceptic candidates (William Hague from 1997–01, Iain Duncan Smith from 2001–03, and Michael Howard, 2003–05) have not always fared so well as party leaders – and often significantly less well than Mr Cameron.

Professor Nicholas Crowson, Head of History Department and Professor of Contemporary British History

Author: The Conservative Party and European Integration Since 1945 (2007) and Britain and Europe: A Political History Since 1918 (2011)

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