Denmark's former prime minister has warned Tony Blair to "take your time" before launching a euro referendum.

Poul Nyrup Rasmussen took his party to defeat in a Danish single currency referendum two years ago.

The Social Democratic Party leader's defeat sent shock waves throughout the European centre left and heralded the electoral demise of Rasmussen's pro-EU government just over a year later.

Developments were monitored closely in London - Denmark is an EU country almost as eurosceptic as Britain - and gave European social democrats an early warning of electoral troubles ahead.

A close ally of the UK prime minister, Rasmussen's intervention is a further blow to single currency enthusiasts.

Asked in a ePolitix.com interview what advice he would give Blair on how to fight and win a euro referendum, Rasmussen replied: "First, take you time".

"Second: Make your preparations properly and fundamentally," he cautions.

Denmark's former PM echoes those in the euro-cautious Gordon Brown camp with his call to avoid a referendum at a time of turbulence in the world economy.

"You should avoid a referendum coming at a time when you have global problems of an economic character," he told this website.

"My advice is: Make the planning for a referendum in a period of economic stability in Europe. Then I really think it would be possible to obtain a 'yes'."

Rasmussen recalls the moment his euro-campaign flopped.

"I remember with our campaign when I stood up - on television news - and said the euro is very strong and it will be a enormous plus for Denmark to be part of the umbrella so we secure finances in to the future. Ten seconds later the euro is dropping dramatically compared to the dollar," he remembers.

Volatile markets may not be an indicator of the real strength or weakness of the euro-zone but were enough for Denmark's voters, Rasmussen recollects.

"We can understand it as economists but it is an enormous leap for me to say the euro is strong and 10 seconds after the euro is dramatically falling in exchange-rate to the dollar," he said.