As a new poll shows continuing public scepticism about joining the euro, Charles Kennedy has urged the prime minister not to back away from holding a referendum on the issue.

The Liberal Democrat leader said it would be "quite wrong" for the government to adopt a "timid" approach to the euro amid concerns that the public remain overwhelmingly hostile to British membership of the single currency.

Of the 2000 questioned for the new survey, 57 per cent were against Britain adopting the euro with just over a fifth in favour. The survey, by FX Currency Services, found 14 per cent to be undecided on the issue and eight per cent not bothered either way.

The survey will come as a blow to pro-euro campaigners, particularly among government ministers, who were buoyed by a recent poll that concluded a vote was "winnable".

But the Liberal Democrat leader told the government not to lose its nerve on holding a referendum.

"My worry is that faced with a haemorrhage of confidence and trust on vital domestic public interest issues like transport, like health, like education, like crime, that the reaction in Downing Street will be to say we have to be timid prime minister, we can't push the boat out on a euro referendum when we haven't sorted out our own back yard. And that would be quite the wrong response," Kennedy told BBC Radio 4's Today programme.

Support for the euro was found to be greater among men, with 27 per cent in favour compared to just 16 per cent of women. The survey also discovered that the majority of those in favour of the single currency are aged between 45 and 54, with 62 per cent of both those in the 18-24 age group and the over 55s against it.

There were also regional differences; a quarter of Londoners and 28 per cent of Scots were pro-euro, while 65 per cent of the Welsh and 68 per cent of those living in the East Midlands were opposed to the currency.

"It's not surprising that the public oppose the euro by two to one when the British rate of unemployment is nearly half the eurozone rate and when a number of eurozone countries have experienced serious internal political problems," said James Frayne, a spokesman at Business for Sterling.

"The British economy is doing well outside the euro - giving up control would take us straight to boom and bust."