Britain is odds-on to join the euro by 2014, according to bookmakers.
The news comes as the pound falls to its lowest ever level against the European currency. A euro is now worth 87p.
William Hill have opened a book on the pound being abolished and replaced by the new national currency.
It is offering odds of 2/7 for Britain adopting the currency by 2014 or later.
"There seems to be an inevitability about the euro replacing the pound eventually - but the big question is when a government will have the nerve to do it," said spokesman Graham Sharpe.
The company is offering 20/1 it will happen next year, 14/1 for 2010, 10/1 for 2011, 9/1 for 2012, 8/1 for 2013 and 2/7 for 2014 or later.
But in an interview with Apprentice star Sir Alan Sugar today, Gordon Brown promised there would be no change to the currency.
When asked by Sir Alan if he "can still keep all my pounds and fivers?" the prime minister answers: "Absolutely, and you can use them to buy your Christmas presents this year, and next year and beyond."
Earlier in the month European Commission president José Manuel Barroso caused a minor political storm when he admitted talking to British officials about joining the currency.
This prompted denials from pro-European business secretary Lord Mandelson and calls from shadow foreign secretary William Hague for details of meeting between Mr Barroso and British officials.