Quietly, measures have been passed forbidding counterfeiting of euro coins and notes in Britain or to use the forged currency inside the UK.
The move has outraged Eurosceptic MPs, who say the euro is being introduced into Britain by the back door. The UK has not yet held a referendum on whether to join the single currency.
"It appears to be the case that euros will be coming into Britain even though we have decided not to join," said Bill Cash, the leading Tory Eurosceptic MP, who sits on the Commons European Scrutiny Committee. "It may be that we have opted out of it but that doesn't mean to say that we are immunised from it. It is creeping in."
The Treasury says euro notes and coins will be valid in Britain when they become legal tender in other European countries in 2002. The euro has been traded by banks since 1 January.
"There will be notes and coins circulating in Britain from 2002. They will be legal tender," said a Treasury spokesman. "They will not be everywhere but it will be possible to use them from that date."
Many businesses, particularly shops near ports and airports, are expected to accept euro currency to attract foreign trade.
But the Government had evidence that the Italian Mafia, which is stockpiling massive quantities of forged euro currency, may be planning to target Britain, dumping their notes and coins in shops.
Ministers decided to introduce the same tough new laws as those in European countries which have already joined the single currency, making counterfeiting the euro a crime under the Forgery and Counterfeiting Act.
The Government has also taken the unusual step of extending its jurisdiction outside the UK to catch criminals who forge euros in Britain.
Until now, Britain has exercised this power only for very serious offences, including crimes against humanity or compromising national security.
Evidence that the Mafia has already printed millions of counterfeit euro banknotes came through the National Criminal Intelligence Service.Reuse content