DAVID Cameron today insisted all options for Britain's future relationship with Europe remained open, a month before he makes his long-awaited speech on the controversy.
But, asked directly if he could "ever imagine Britain leaving the EU", the Conservative leader revealed: "It's not a position I support, so I don't spend my time thinking about it.
"But clearly, all futures for Britain are imaginable. We are in charge of own destiny, we can make our own choices.
"I believe the choice we should make is to stay in the European Union, to be members of the single market, to maximise our impact in Europe, but where we are unhappy with parts of the relationship we shouldn't be frightened of standing up and saying so."
Updating the Commons on last weekend's European Council summit in Brussels, Mr Cameron revealed when he would address the issue, having reportedly delayed the speech several times in the past few months.
Last week Mr Cameron claimed he was using a tantric approach to the speech, saying: "It will be even better when it does eventually come."
"I will be setting out in the speech in the middle of January the pathway that we should take for the future," he said today.
"Because of the change process in Europe, we require some tactical and strategic patience here in the UK to see how that change is going to pan out so we can get our response to it right.
"That will be the time when we have the maximum amount of influence when Europe is making big changes itself."
Labour leader Ed Miliband challenged Mr Cameron to confront Cabinet colleagues pressing for an in-out referendum.
Mr Miliband urged the Prime Minister to end "the dither and delay" and clamp down on senior ministers voicing their opinions on whether the UK should pull out of the EU.
He claimed Mr Cameron was "stranded between the party interest and the national interest", adding: "The problem is no-one else in his party is holding back."
The Labour leader told MPs: "Why does he let member after member of his own Cabinet brief they are open to leaving the EU, including most recently the Education Secretary?
"The drift in his party and the direction of his policy mean we are sleepwalking towards exit."
Foreign Secretary William Hague previously said an in/out poll was "the wrong question at the wrong time" and would create economic uncertainty, while Education Secretary Michael Gove reportedly believes the UK should reclaim its sovereignty and Defence Secretary Philip Hammond has said the current balance of powers is "not right".
Speaking outside the Commons, shadow foreign secretary Douglas Alexander said he believed the UK Independence Party's (Ukip) surge in the polls, coupled with demands from eurosceptic Tories, were forcing the Prime Minister's hand.
Mr Alexander said: "He seems to be being driven by external pressure from Ukip and internal pressure from his backbenchers towards an in-out referendum in contradiction of what he himself was arguing only a few weeks ago."
In his Commons statement, Mr Cameron told MPs the concessions he won over the planned European banking union were important for boosting growth and jobs in Britain.
The Prime Minister said: "There is also an explicit clause that says no action by the European Central Bank (ECB) should directly or indirectly discriminate against those countries outside of banking union.
"This is vital for our financial services industry which must continue to be able to provide financial products in any currency."
Mr Miliband said the summit failed to deliver a plan for growth, but welcomed the supervision the ECB would have over the eurozone.
He added: "The most important issue is not necessarily who supervises which banks but who takes responsibility for bailing out failing banks in the euro area.
"That is what will deliver the firewall we need between bank and sovereign risk."