David Cameron faces the prospect of the biggest rebellion of his premiership later today, with dozens of Conservative MPs threatening to defy him over the issue of Europe.

Rebels suggest that around 70 Tories could ignore a three-line whip to back a motion calling for a referendum on the UK's membership of the European Union. Mr Cameron is not expected to lose the vote, which carries no legal weight, but the threatened revolt is being seen as a test of his authority, in a crucial week for Europe.

Speaking on the programme the Foreign Secretary William Hague warned that the motion was asking "the wrong question at the wrong time".

"It was not in the manifesto of either of the governing parties, it cuts right across the rules for holding referendums that we have just agreed by large majorities, it would create additional economic uncertainty," he told presenter John Humphrys.

"Europe is undergoing a process of change, and an in/out referendum... people would want to know where the change was going to finish up before they voted, clearly an in/out referendum is not the right idea."

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