William Hague has branded the eurozone a "burning building with no exits" amid frantic efforts to control the sovereign debt crisis.
The Foreign Secretary said he believed Germans would have to subsidise weaker members such as Greece for "the rest of their lifetimes".
Delivering the starkest comments so far by a senior British minister, Mr Hague also claimed the single currency was set to become an "historical monument to collective folly".
The intervention emerged as the president of the European Commission, Jose Manuel Barroso, warned that the EU faced its "greatest challenge".
However, Mr Barroso insisted Greece would remain in the eurozone despite fears that it will default on huge debts.
Interviewed for The Spectator magazine, Mr Hague referred to a remark he made as Tory leader in 1998 while running a campaign to 'Keep the Pound'.
"I described the euro as a burning building with no exits and so it has proved for some of the countries in it. But there are no exits," he said.
He went on: "You can have burning buildings where they manage to put out the fire or control it or get more room or something.
"I might take the analogy too far but the euro wasn't built with exits so it is very difficult to leave it."
Mr Hague warned that eurozone countries had to take difficult choices, without exchange rate flexibility to ease the pain.
He suggested that "Greeks, or Italians or Portuguese have to accept some very big changes in what happens in their country, even bigger than if they weren't in the euro, and Germans will have to accept that they are going to subsidise those countries for a long time to come really, for the rest of their lifetimes".
The Cabinet minister said the continent was now having to deal with the fallout from the creation of the euro.
"It was folly to create this system, it will be written about for centuries as a kind of historical monument to collective folly. But it's there and we have to deal with it," he said.
Mr Hague also reiterated his desire for Britain to take back powers from Europe - a key demand of many Conservative right-wingers.
"The EU does have too much power," he said. "I haven't changed that view since being in government, in fact if anything, being in government has reinforced that view. There should be powers that are returned to this country.
"I think we should be clear in the Conservative party that that is where we are heading."
He appeared to play down the prospect of making progress on the issue while the Tories were in government with the pro-Europe Liberal Democrats.
The "answer to any hypothetical question about what the coalition would do is: we'll have to discuss it in coalition", he said.
Europe was likely to be "one of the dividing lines between the coalition parties, put forward at the next election", Mr Hague added.
Ukip leader Nigel Farage said: "William Hague thinks the euro is awful, he thinks the EU is awful, but he wants the people of Britain to wait for four years before he will do anything about it. This he blames on the Lib Dems.
"If the euro is a burning house, we are in the conservatory. He won't even make a move towards the exit, despite the flames licking around the country's legs.
"At the moment it is clear that the singed trousers in this relationship are worn by Nick Clegg."