Boris Johnson has spoken out against holding a referendum on whether the UK should remain part of the European Union as it currently exists, in an intervention that will help the prime minister, David Cameron, as he faces concerted pressure from hardline Tory backbenchers for an in/out vote.
The mayor of London, seen by many Conservatives as a potential future leader and alternative to Cameron, and who has channelled strident Eurosceptic sentiment in the party, said that any further fiscal integration of the EU should trigger a referendum but that a single question on whether the UK should remain a member state was unnecessary.
Johnson made his intervention from India, where he is leading a trade mission, telling BBC Radio Five Live: "I certainly think that if there was to be a new treaty, for instance on a fiscal union or on a banking union or whatever, then it would be absolutely right to put that to the people.
"Whether you have an in/out referendum now, I can't quite see why it would be necessary."
Cameron has given his backing to a referendum on the EU, but has made clear that such a poll would not pose the in/out question sought by many in his party. Instead, he envisages that it would be about changing Britain's position within the union.
Johnson said that what worried him were changes in the way that the EU was initially constituted, adding: "It is becoming the eurozone de facto, and the eurozone is not something that we participate in."
But he went on to describe why the prospect of Britain's withdrawal from the EU in its current circumstances would not "appeal", stating that the UK would not be able to sit in the council of ministers and would be without a vote in that body's deliberations.
"What you could do is think of a new arrangement, new areas of the treaty that we didn't want the budget to take in any more. That is where people are thinking now so with greatest respect to the in-outers, I don't think it does boil down to such a simple question."
His comments effectively distanced Johnson from calls by hardline Tory MPs for a straightforward in/out referendum.
Mark Pritchard, an influential eurosceptic Conservative MP and a former secretary of the 1922 committee of Tory MPs, banged the drum on Sunday for the referendum when he urged ministers to bring forward legislation before the end of the parliament.
"This should be an in/out referendum – anything short of that simply won't deliver," he wrote in an article for the Telegraph website.
The foreign secretary, William Hague, reiterated on Sunday that there would be a referendum to seek "fresh consent" from voters in the wake of renegotiation and the eurozone crisis.
"We do believe that sometimes less is more in Europe; that doing less at the European level is better for this country and for other countries, and what we've said is that when we see how that crisis in the eurozone plays out and when we've tried to improve our relationship with Europe, well that will be the time to seek fresh consent from the British people and the cleanest and clearest way of doing that would be in a referendum," he told the BBC's Andrew Marr Show.
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