The president of the European Central Bank has warned that the UK may not be able to join the European single currency for many years, even if it wanted to.

The UK Government has indicated that it will assess whether it is in Britain's interests to adopt the Euro in a few years time, before putting the matter to a referendum.

But Wim Duisenberg has told the BBC that the decision on whether the UK should or could join was not just down to the British Government.

Mr Duisenberg, who is responsible for the day-to-day running of the Euro, said the UK's economy would have to become more like those on mainland Europe if it is to join the other single currency countries - and that could take several years.

In an interview to be broadcast on BBC 2's The Money Programme, on Sunday, Mr Duisenberg said he believed the UK still has to show it was able to share policies with the other members of the single currency.

Euro row

Mr Duisenberg's comments triggered the predictable euro row between government and opposition.

The Shadow Chancellor Francis Maude said ministers were living in a fantasy world.

He argued that there were absolutely no signs the UK economy was converging with those on the continent and accused the government of spending millions of pounds of taxpayers' money on its plans to scrap the pound.

The Trade and Industry Secretary Stephen Byers said Mr Duisenberg had raised some important questions.

In his view, though, the ECB president's comments merely proved that government policy was right. Chancellor Gordon Brown has set five "economic tests" to see whether joining the euro would be in Britain's interests before he will recommend doing so.

The UK has raised interest rates in recent months to tackle inflation, and rates are currently almost twice as high as those of countries in the Euro zone.

Earlier this week, Mr Byers had laid out a timetable for Britain to join the euro early in the next Parliament, if key economic tests were made and it was approved by referendum.

The government is believed to be concerned that foreign investment in the UK could dry up if it fails to signal its intention to join Europe's single currency.