One of the main architects of the single European currency, Jacques Delors, says the eurozone was flawed from the beginning.
Mr Delors, who as head of the European Commission from 1985 to 1995 played a key role in launching the euro, told the British newspaper the Daily Telegraph that the lack of central powers to co-ordinate economic policies allowed some members to run up unsustainable debt.
The comments come amid growing doubts over the viability of the eurozone, the BBC reports.
The 86-year-old Frenchman says the debt crisis stems not from the idea of a single currency itself, but from "a fault in execution" by political leaders who oversaw its launch.
He says they turned a blind eye to the fundamental weaknesses and imbalances of member states' economies.
"The finance ministers did not want to see anything disagreeable which they would be forced to deal with," he says.
Mr Delors insists that all European countries must share the blame for the debt crisis. "Everyone must examine their consciences," he says.
Commenting on those - like the British - who objected to euro membership by saying the currency could not work without a sovereign state behind it, he says: "They had a point."