Some mistake? Labour spokespeople later denied Miliband was commenting on Labour policy at the next election.

Accident or design? Miliband lets slip his Europe policy

Accident or design? Miliband lets slip his Europe policy

Labour will go into the next election opposing an in-or-out EU referendum, Ed Miliband appeared to reveal today.

It was unclear whether the Labour leader meant to state his EU policy, as he seemed to let the comment slip under sustained pressure from David Cameron at PMQs.

"Our position is no, we do not want an in-out referendum," Miliband said, toward the end of a particularly raucous session.

The prime minister clearly failed to hear the admission, because he pressed on with his questioning as if Miliband had still not revealed whether he backed his calls for a referendum on membership.

"I have politely to say to the honourable gentlemen that his whole argument about uncertainty is undermined by his inability to say whether he supports a referendum or not," Cameron said.

The Miliband admission ensures Europe will be a clear dividing line at the next general election. Tories will be jubilant they can go to the polls promising the public a choice on Europe and constantly pointing out that Labour wants to prevent it.

Labour spokespeople later insisted nothing had been decided on policy at the election and that Miliband was merely insisting he oppose a referendum at this moment.

Polling regularly shows public support for a referendum on the EU and usually that a majority of voters would chose to leave – although that latter trend is dependent on the context in which the poll conducted.

Cameron's policy, which was revealed this morning in a speech in central London, would see the UK renegotiate its membership of the EU into a looser, more flexible arrangement, and then offer an in-or-out referendum to the public, probably in 2017.

The speech saw the prime minister praised in gushing terms by his usually rebellious backbenchers, although there have already been murmurs of discontent, particularly over his intention to campaign for the UK to stay in the EU.

If the Tories win the next election and carry out the referendum, it could once again tear the parliamentary party apart.