Speaking to the London Chamber of Commerce today, Peter Mandelson will warn that remaining outside the single currency will limit Britain's influence inside the European Union.

He will suggest that if the current review of the Treasury's five tests is negative the government should take a "final look" at the issue next year.

Today's Times reports that European insiders have believe that a British decision to stay out of the euro will reduce Tony Blair's ability to influence the future shape and direction of the EU.

The FT reports that Britain, Sweden and Denmark - the three EU countries that have not joined the single currency - have now been excluded from preparations for the monthly "eurogroup" meetings.

Meanwhile, Robin Cook is said to be set to warn that ruling out a single currency for this parliament would have serious political and economic consequences.