By Matt Chorley, Mailonline Political Editor PUBLISHED: 09:29 EST, 22 January 2013 | UPDATED: 10:16 EST, 22 January 2013 Prime Minister David Cameron, pictured outside Number 10 today, is due to deliver his long-awaited speech on Europe tomorrow Dozens of Tory MPs are to launch a campaign to keep Britain in the European Union, fearing ties with Brussels could be severed almost by accident. David Cameron will use his long-awaited speech on Europe to warn Britain could ‘drift towards the exit’ without major reforms before pledging a referendum on membership of the EU. More than 30 pro-European Conservatives are preparing to back the idea of a full in/out referendum, believing the anti-EU faction of the party has dominated the debate so far.
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More than 30 'Euro-realists' back an in/out referendum believing British will vote to remain part of the European Union
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David Cameron to deliver long-awaited Europe speech in London tomorrow
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PM under pressure to appease Eurosceptics fearing the rise of the UK Independence party in the opinion polls
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Lib Dems accuse Tories of 'throwing crockery' at Europe
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The Prime Minister has made clear he wants the UK to remain in the EU only if significant powers can be returned from @placeholder.
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Extracts released last week showed that he will use the speech to warn @placeholder leaders that Britain could leave the 27-nation bloc if three key concerns are not resolved.