Government ministers are now working towards "E Day" - the code name for the hypothetical moment when Britons enter the euro.

A document from the Office of the Deputy Prime Minister, seen by the Times, also discusses the problem of "smoothing" where prices would be rounded up. It suggests the problem would be widespread.

It urges local authorities to prepare strong PR campaigns to boost the euro.

Meanwhile, the Conservatives have accused the government of wasting taxpayers' money in an attempt to disguise any rise in the price of public services.

The Mirror reports that Nancy Dell'Olio, girlfriend of England football manger Sven Goran Eriksson, has joined the debate with a call for Britain to join the single currency.