William Hague raised doubts about the future of the euro today, saying it was impossible to know whether the currency would collapse.
The Foreign Secretary, a vociferous and long-standing critic of European monetary union, said he "hoped" that the euro would survive, but added: "Who knows?"
His comments came as talks continued about the possible need to bail out debt-ridden Ireland, the latest crisis-hit eurozone member.
Asked whether the euro could collapse, Mr Hague told BBC Radio 4's Today programme: "Well I hope not.
"No-one has pointed out more of the problems than I have over the years in having a currency where we lock together the exchange rates and interest rates of countries with different economies.
"But I very much hope not. Who knows?
"If an economist knew that, let alone a politician, they would be very gifted people, but clearly we want to make sure there is stability in the eurozone and irrespective of the eurozone there is a specific case for assisting Ireland if Ireland asks for that assistance."
The Government has repeatedly stressed that Dublin has not requested financial help, despite pressure from within the European Union for it to accept a package to calm jittery markets.
Officials from both the European Commission and the International Monetary Fund were in the Irish capital today to discuss the options for ensuring Ireland can cope with its struggling banks.
Mr Hague said: "It's very much in the British national interest for the eurozone to be stable, however much we pointed out all the faults that it would have, and I pointed them out more than most.
"But the fact is that it exists and a very serious problem in the eurozone affects our economy, the jobs and the businesses in our country."
The UK had a particular interest in supporting Ireland because of the inter-connectedness of the two countries' economies, he added.
"We stand ready to assist in the case of Ireland although no formal request has been made for that assistance, there are meetings that are going on on a precautionary basis," Mr Hague said.