British Prime Minister David Cameron will threaten to back the campaign to take the UK out of the EU in a future referendum if his calls for reform are not met, according to Conservative party sources. 

Cameron is actively considering toughening his stance towards Europe, The Times yesterday (24 August) reported. 

He has previously said he wants the UK to remain in a reformed EU but warned other EU leaders in June that the appointment of Jean-Claude Juncker as Commission President could hasten “Brexit”.

A source told the Times, “The shift was almost made public at the time Juncker was appointed, but that timing might have looked like petulance.”

While the timing of the public threat has not yet been agreed, it could come at next month’s Tory Party conference. Cameron has said he wants to stop more powers being transferred to Brussels and cut red tape for businesses.

He has pledged to hold an in/out referendum on the UK’s membership of the EU in 2017 if he is returned as PM in next year’s general election.

Ahead of the May 2015 poll, Cameron finds himself under pressure from the popularity of the UK Independence Party. The Eurosceptic party could poach Tory seats as it builds on its spectacular success in May’s European elections.

The story broke after London mayor Boris Johnson called on Cameron to declare if he was prepared to walk away from the EU.

Johnson, a potential rival for the Tory leadership if Cameron doesn’t secure a majority at the election, said, “ ‘I think we can get there [to a reformed EU]; but if we can't, then we have nothing to be afraid of in going for an alternative future, a Britain open not just to the rest of Europe but to the world.”

The new attitude risks alienating his coalition partner Nick Clegg, the deputy prime minister. Clegg has previously warned that threats of Brexit are no way to negotiate EU reforms.

Clegg warns ‘Brexit’ threat no way to negotiate EU reforms on EurActiv

Clegg warns ‘Brexit’ threat no way to negotiate EU reforms

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Cameron's defeat by Juncker

Cameron’s warning that Junker’s appointment could led to Brexit was ignored by other EU leaders who voted 26 to two in favour of the Luxembourger.

That led to widespread criticism of Cameron in the UK and wider EU and to renewed speculation about the UK quitting the Union.

Critics accused the Conservative leader of grandstanding in Europe to placate the Eurosceptic elements of his party.

At the time Cameron told the UK Parliament, “We will fight with all we have to reform the EU.”

Opposition leader David Miliband criticised Cameron’s strategy of threatening Brexit.

He said in the debate, “His combination of threats, insults and disengagement turned out how to be a masterclass in how to alienate your allies [...]The rest of Europe lost patience with his act […] the strategy of threatening exit from the EU was put to the test and failed.”

​EU diplomats struggled to understand Cameron's strategy, which left the UK looking more isolated than at any time since a December 2011 summit.

There Cameron vetoed new fiscal rules for the eurozone, a position only the Czech Republic shared at the time, although it too has now backed the fiscal compact. Other EU leaders got around the British blockade by concluding a separate treaty outside the EU framework.

EU diplomats struggle to understand Cameron's strategy on Juncker on EurActiv

EU diplomats struggle to understand Cameron's strategy on Juncker

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