David Cameron risked fuelling eurosceptic anger today by bluntly dismissing the prospect of an in-out referendum.
The Prime Minister said he was governing for the "whole country", and would not back a "false choice" between staying in the European Union or leaving.
However, he also appeared to confirm that a referendum will be held if the crisis in the eurozone leads to a new treaty.
The comments came in a round of broadcast interviews at the Conservative Party conference in Manchester.
Right-wingers at the gathering have been demanding a popular vote on EU membership, saying the debt crisis in the single currency area reinforces their arguments.
But Mr Cameron said: "I don't think most people in the country want that choice between in or out.
"I think most people in the country recognise that our interest is to be in this organisation, fighting for a strong market for our goods and services.
"I'm going to have to be Prime Minister for the whole country.
"The point is, what people really want is not a choice between in or out, and the Europe we have now - that, frankly, I am not happy with - and the sort of relationship (where) we get something back for it.
"That is what we should be fighting for, rather than a sort false choice of in or out."
The premier said he was acting in "Britain's national interests" by encouraging the eurozone to integrate further to tackle its problems.
He stressed that non-single currency members would require "safeguards" to protect their interests as the necessary reforms were implemented.
Mr Cameron admitted that European leaders had not reacted decisively enough to deal with the Greek debt problems over the summer.
Asked if there had been a lack of urgency, he told ITV News: "I acknowledge that.
"Part of the problem is the Greek programme that was put in place, the milestones that they have to hit, people in the eurozone expected that to happen.
"That has not happened."
Quizzed on whether he expected the EU to negotiate a new treaty to facilitate closer eurozone integration, Mr Cameron said: "I think at some stage in the future, yes."
Pressed by Sky News whether that meant there would be a referendum, he went on: "Yes, at some stage in the future it is likely that there will be a treaty.
"But in the early stages of this will be the eurozone countries, I think, doing more together."
He added: "There might be a treaty later on and then all the issues about the referendum and everything else will come up.
"But I think let's not get ahead of ourselves."
Mr Cameron acknowledged that the UK's economic situation was worse than when the coalition came to power.
"Yes. I am not an economic forecaster, but if you look at the forecasts they are less good now than they were then," he said.
"But they are still forecasting growth. We must not talk ourselves down."
He went on: "Obviously we face a worldwide slowdown. The French economy has stalled, the German economy has stalled. Even the mighty America has issues."
The Prime Minister said it was crucial that the Government stick to its deficit reduction plans in order to keep interest rates down.
However, amid criticism from senior Tories and Labour of a lack of measures to boost growth, he highlighted measures to help people start and grow businesses.
Mr Cameron said freezing council tax again next year was a "important step" that would help families deal with the "tough" conditions.
And he defended funding for weekly bin collections, saying in a "civilised country" people wanted their "smelly food waste" removed more regularly.
He insisted the Government was able to commit more money without breaking its budgets because savings were being made, pointing out that the civil service headcount was at its lowest level since the Second World War.
"I hope people will look at the Government and say, at least the Government as well are cutting their own costs," he said.
Mr Cameron rejected the suggestion that he could not understand what people were going through as he had never experienced financial hardship.
"I think what matters in leadership is do you listen to people, do you understand their concerns?" he said.
He also reiterated his regret over incidents where he was accused of using patronising language to Labour MP Angela Eagle and Tory Nadine Dorries.
"I think in the House of Commons - this is not an excuse, it's just an explanation - sometimes it is very aggressive and confrontational," he said.
"Words came out of my mouth that should not have done and I needed to put that right."