Tony Blair last night gave his strongest signal yet that he would not try to take Britain into the euro if Labour wins the General Election.

The Prime Minister said that it "doesn't look very likely" that the economic conditions would be right to recommend in a referendum that Britain should sign up to the single currency.

"It doesn't look very likely at the moment that your economics are going to change dramatically," he said.

"If the economics aren't right, if it won't help your country economically, you don't do it. Now, at the moment there is no part of business and industry clamouring to say we need this for our economy, so it doesn't look very likely."

His comments follow a speech this week by Gordon Brown emphasising that the Treasury's five tests must be met before the Government would hold a referendum.

Mr Blair did however indicate that Labour could drop its plans for a referendum on the new European constitution, if the treaty was abandoned by the EU member states.