The Foreign Secretary made it clear that he believed the election victory for the socialists under Lionel Jospin and the aborted attempt by the Germans to revalue their gold reserves had raised doubts about the single currency starting on time in 1999.
Mr Cook is one of the leading sceptics in the Cabinet about the single currency, but there appears to be no difference of view within the Government "big four" - Tony Blair, Gordon Brown, John Prescott and Mr Cook.
In spite of the warmth of the meeting between Mr Blair and Mr Jospin in Malmo last Friday, Britain is wary about the French plans for softening the entry criteria for the single currency.
Asked if he welcomed the French idea of a "softer euro", Mr Cook said: "No, not if that meant you were making it easier for people who had fudged the criteria to get in under the line."
He added: "The debate at the moment seems to be in danger of polarising between a softer Euro, which would not be workable, and a harder Euro which would not be popular.
"If the European single currency is to proceed on time it is very important that it proceeds on time both with credible criteria which will make sure it is a credible strong currency and secondly with popular backing."
Mr Cook was also dismissive of some of the five points by Mr Jospin at the social democrats' gathering in Malmo.
Mr Jospin said Italy and Spain should be included in the first wave. But Mr Cook said: "I don't think you should name countries who ought to begin, as of right. I think countries should be entitled to join a single currency if they meet the criteria
He said there was now broad agreement in Europe that the approach to a single currency had to be underpinned by an economic strategy for growth and jobs.
That was why Mr Brown, the Chancellor, would be putting his proposals today for jobs to the meeting of European finance ministers.
It was "unlikely" Britain would join the first wave in 1999, said Mr Cook, but he stressed that jobs would be the key yardstick for Britain's decision on whether to enter the currency, if and when it started. "We will carry out a hard-headed assessment towards the end of this year as to whether joining would be in the economic interests of Britain; would it increase or risk jobs.
"At the moment, we think it unlikely that that assessment would put to us joining," he said on BBC Television's Breakfast with Frost.Reuse content