Controversy over British membership of the euro has been reignited after it emerged that Business Secretary Lord Mandelson said it was "obviously" still an objective of the Government.
Conservatives said it was "deeply disturbing" that Lord Mandelson should raise the issue at this point.
They claimed that Britain would have suffered more in the recession if it had not had the freedom to lower its own interest rate.
But Lord Mandelson insisted that the European single currency had been "a great success" during the downturn.
"It is perfectly clear that the euro has been a great success in anchoring its eurozone members during this financial crisis," he said, in remarks following a speech in Berlin.
Asked if the British Government would consider joining the euro, Lord Mandelson replied: "Does it remain an important objective for Britain to find itself in the same currency as that single market in which it interacts? Obviously yes.
"That has to be a decision taken on the right terms, in the right circumstances and conditions, and therefore at a future time than we have now."
A spokesman for the Business Secretary said that he was restating the long-standing Government policy that it would be beneficial for Britain to join the euro in the long term, but only when the conditions were right, and had made clear that the time was not right now.
But shadow foreign secretary William Hague said: "It is deeply disturbing that the man who now makes most of the Government's policies has declared that Britain should join the euro.
"The fact is that if we had scrapped the pound, interest rates would have been lower in the boom and would now be higher. Under the euro, Gordon Brown's boom and bust would have been even deeper. Lord Mandelson's failure to learn this obvious lesson shows how bereft Labour are of fresh thinking."