In an unpublished report, which has been submitted quietly to the Commission and obtained by The Independent, the Chancellor details the measures the Government is taking to prepare the UK for entry.
Ministers said last night that Mr Brown's "convergence programme" was aimed at allowing Tony Blair to call a referendum on joining the euro shortly after the next general election if Labour retains power. If an election were held in 2001, Britain could join by January 2002, when euro notes and coins start circulating.
However, cabinet sources said there was "an outside chance" of a referendum before the election after the euro's successful launch last week. "If the business community pushes hard, then the momentum may become unstoppable," one senior minister said.
John Redwood, the shadow industry secretary, said: "This document is part of the softening up process, designed to create the impression that joining the euro is inevitable. We think that is rubbish."
Mr Brown's document said the Government was pursuing a strategy "for achieving the stability and convergence" required for Britain to join. The traditional differences between the British economy and those of its EU partners "are becoming less distinct over time", it added.
The Government's policies "should improve the flexibility of the economy... helping to ensure that the UK could maximise the benefits of the single currency".
The Chancellor told the Commission that "to ensure that membership is a genuine option, both public and private sectors are beginning to prepare for the single currency".
The document emphasised the importance of a stable exchange rate for the pound. "The Government is confident that the new arrangements provide the best platform to deliver greater stability in the sterling-euro exchange rate," it said. "Over time, it will allow the UK economic and interest rate cycle to move closer to that of the single currency area."
The fact that UK interest rates, at 6 per cent, are double those in the euro area is explained as a legacy of past volatility in the British economy.
The Maastricht Treaty requires sterling to rejoin the exchange rate mechanism, from which it was forced out in 1992, although a period of stability would probably be acceptable to other EU members.
Mr Brown told the Commission he was due to present a National Changeover Plan outlining the steps necessary for Britain to join the euro "early in the New Year". However, its publication is likely to be delayed until next month, because of the resignation of Peter Mandelson, the former Trade and Industry Secretary, who was helping to draw it up.Reuse content