The long-serving Commission president (1985-1994) attacked European Council President Herman Van Rompuy for not defending the community method, and EU leaders for "completely destroying the heritage of the fathers of Europe".
He also took aim at the European Commission and its president, JosĂ© Manuel Barroso, for its lack of initiative and for playing the "pyromaniac fireman" on the eurozone crisis.
Among the EU's national leaders, he pointed the finger at French President Nicolas Sarkozy and German Chancellor Angela Merkel.
Delors made these statements in the European Parliament, where he gave his backing to an appeal "For a European Socialist Alternative", which he said represented "an offensive of Social Democracy in the broader sense".
Speaking to a like-minded audience, Delors said that the European Council, which brings together the EU heads of states and government, was "morally responsible" for the economic crisis.
Nationalistic power play
Delors said that in recent years, the European method had been "disguised", marking a return to the 1814-1815 Congress of Vienna, and to the "cynicism" of nationalistic power play.
"If we go this way, it means that someone wants to kill Europe, that it should not exist and should not have existed in the first place," he said.
He briefly referred to Sarkozy, accusing him of trying to "reassure" the French people by telling them that intergovernmentalism in Europe was the rule, as if "Europe could be French".
Addressing directly Van Rompuy, who is discretely steering EU summits since he took office two and a half years ago, he said:
"No, Mr. Van Rompuy, you are not defending the community method â€¦ The community method is the constant primacy of the European interest. It should be the fight of each Commissioner to be there not because it's nice to be there and because the job is well paid, but to be there for the sake of the European interest."
Referring to the fact that often leaders explain that the solutions found are the only possible under the circumstances of the economic downturn, he said:
"Careful with this explanation given to us now, and which aims to completely destroy the legacy of the fathers of Europe. Because this is what is at stake, under the pretext of urgency or I don't know what."
Delors, who called the European Parliament's Socialist and Democrat group members who hosted the meeting his "comrades", said the current EU was "the reverse" of what he tried to achieve in the 1980s and '90s. Social dialogue and the community method are on the decline, he warned, and are being replaced by a surge of individualism and inter-governmental solutions, promoted by the conservatives.
Solidarity on the decline
"I regret to say today that social dialogue is absent. And why does this upset me? Not because it's the opposite of what I was trying to do, but because the dialogue is together with the parliamentary system, a cornerstone of democracy," he said.
Delors said that the main cause of the crisis was "the excess of the ideology of financing" and a philosophy, according to which the added value was "the increase in share price".
He said that the EU leaders of the eurozone were "morally responsible" for the crisis, and that they ignored his proposals, made in 1997 in his capacity of president of the Notre Europe think-tank, to coordinate economic policies.
Instead, leaders only added the word "growth" to the name of "Stability and Growth pact", he said.
"What nonsense, what folly, what irresponsibility!"
Delors however confessed of having made a mistake, namely in believing that while federalism was not possible, cooperation could be an alternative. He further explained that what happened is that the common market with a common currency led to a greater diversification of productivity in the interest of Germany and to the detriment of others.
"Europe is built on diversity. Should it live on this diversity, or should it accept an implicit rule of Germany, that is the question," he said, alluding to Shakespeare in English.
Closer cooperation vs. 'punitive methods'
Delors said EU leaders had refrained fromÂ the method of closer cooperation, put in place by the 1992 Maastricht Treaty, according to which some countries can work more closely in certain fields without prejudice to the community method.
"Whatever the challenges of Schengen, and they largely come from Sarkozy, would there ever be Schengen countries if a few countries did not try to do it?" he said, referring toÂ French president's electoral speech, which called for radically changing the way the Union manages its common borders.
"The euro area should be an area of enhanced cooperation with its own instruments, that's what we missed," he said, adding that "transfer instruments" were needed in a situation where the only such instrument â€“ revaluation and devaluation â€“ is impossible.
DelorsÂ blasted the "fiscal compact" treaty, calling it a "gas factory" (usine Ă gaz), a French expression meaning that it was a big effort producing little result. He said that the growth element was missing, and it was unclear who decided what.
Delors said he had made an effort to make sense of the fiscal compact, of the 'six-pack' "and the rest", putting everything on a same 7-page paper, but regretted that it didn't make much sense to him.
Instead of decisions taken by the 17 eurozone countries, which he said would lead to nothing, he pleaded in favour of delegation of powers and a "focus of federalism".
"The question is as brutal as that", he said.
He pleaded for politics to govern Europe, instead of "punitive rules", adding that all countries could not adopt the German model, nor was this needed as the EU was a 'union of diversity'.
Delors blasted the Commission's dealing with individual countries in difficulty, taking as an example Spain under its current centre-right government, for which he said he had no particular sympathy or antipathy.
"The Spanish government explained that it could not do more," he said, referring to a recent budget deficit setback. "Immediately, they fall upon him, in the name of what? Of the fear of markets. But this is the pyromaniac fireman! In saying that, they panic markets even further. Where is the responsibility of these people," he exclaimed, adding that the US and China were worrying for Europe because of such handling of the crisis.
"It was the cacophony for three years. Where is the responsibility of Europe? They understood nothing!" he said, prompting applause from the audience.
Delors said that Europe had left behind territories prey to poverty, including in France, and that the cohesion policy had failed. He insisted that the alternative was to create eurobonds to create "a financial market for the euro".
"Eurobonds is not a whim of the moment. It is not to come without conditions to the aid of Greece or Ireland. Eurobonds are the necessary complement of the existence of the euro and of a financial market," he said.
Delors said that the "markets themselves" had been clamming for the eurobonds, but only the "stubbornness of Ms Merkel, maybe of others" had prevented the project. He added wittingly that his impressions came from the newspapers, and he was "not the confident" of the German chancellor.