Speaking during a two-day visit to London, the socialist leader denounced U.S. President George W. Bush as an "assassin" who should be imprisoned for his "genocidal" policies in Iraq, and who was trying to provoke a "war of civilizations" between the West and the Muslim world.

Rather embarrassingly for British Prime Minister Tony Blair, one of Bush's closest allies, Chavez was in London at the invitation of outspoken London Mayor Ken Livingstone, known as "Red Ken" for his socialist leanings.

Not surprisingly given his one-time description of Blair as "the main ally of Hitler" because of his close relationship with the U.S. president, Chavez was snubbed by the government during his visit, but received a hero's welcome from trade unionists, members of Parliament -- including left-wing members of the ruling Labor Party -- and a host of celebrities and political activists.

Standing side by side with Livingstone at London's City Hall, Chavez delivered a fiery invective against the U.S. administration, denouncing Bush as "the worst criminal in humanity" who should be put in jail for his actions in the Middle East.

Referring to the U.S.-led invasion of Iraq, he said: "He is an assassin. He is a criminal responsible for genocide, completely immoral. I believe that he should be put in jail."

He warned against taking military action against Iran over its nuclear programs, saying the consequences would be both devastating and unpredictable.

"I know you men and women in London, whatever you are paying for a gallon of petrol it would be more," he said. "The situation would be destabilized against the whole world and that is why we want peace."

Stating that he did not believe Iran was trying to acquire nuclear weapons, he said: "We want dialogue. We are not for war. All we want is respect for the will of the people of Iran."

Chavez played down his previous threats to cut off supplies of oil to the United States if it decided to wage war on Iran.

The Venezuelan leader, who presides over the world's largest oil reserves outside the Middle East, acknowledged that he had said in the past that the United States could "forget about the oil" if it waged war against other countries, but would not be drawn on whether he would carry out that threat. "It depends on the circumstances," he said.

But, he stressed: "We are responsible people. In spite of the aggression from the United States against us, we have never suspended oil supplies to the United States."

Caracas has accused Washington of supporting and funding an opposition coup in 2002 which briefly ousted Chavez from power. The U.S. Congress continues to fund the Venezuelan opposition through the Washington-based think-tank the National Endowment for Democracy, a move which Chavez describes as a resoundingly undemocratic and imperialist attempt to maintain U.S. hegemony in Latin America.

In a characteristically blistering outburst, Chavez rejected claims that he was an "imperialist" prepared to use his country's vast oil reserves to manipulate other nations.

This was "propaganda" created in the West and distributed to journalists and political leaders, he said. "It is absurd. Policy and politics is a sovereign issue, we respect the sovereignty of other nations."

He acknowledged that Venezuela was striving for greater South American unity but insisted that this was on the basis of solidarity, mutual respect and adherence to international law.

It was Washington that did not respect international law, he said, adding: "That is where the empire is."

South American countries were not planning to monopolize their oil and gas but were simply working on integration projects similar to those afoot in Europe, he claimed. He cited Venezuela's work with Brazil, Argentina and Bolivia on a new oil and gas pipeline from Patagonia to the Caribbean, which he said would distribute supplies cheaply for at least 150 years.

"This is a plan for social freedom, to help fight poverty, to have sustainable development," he added.

In what was perhaps a tacit attempt to embarrass the British government, Chavez offered to supply cheap heating oil to Britain's poor through two U.K. refineries in which Venezuela's state oil company PDVSA has investments.

"Maybe we could use these refineries to help in some way the most needy

people here in London and Great Britain," he said. "Above all in winter when the prices go up a lot... and there could be people that can't pay when the temperatures go down. We are doing it in the United States for thousands of people."

The proposal mirrors a similar scheme in the United States, where Venezuela delivered heating oil to the poor in seven states last winter. Some of the oil was sold at a discount, while some of it was donated for free to homeless shelters. The controversial move was seen as an attempt to undermine the Bush administration, which Chavez says neglects poor Americans, and to promote his brand of socialism.

The Venezuelan leader -- who models himself on Simon Bolivar, the revolutionary general who liberated much of Latin America from Spain -- went on to denounce capitalism as a "destructive" system which concentrates the world's wealth in the hands of a few in the form of a ruling elite.

"I have absolutely no doubt that socialism is the way forward. What we need is a new socialist project," he said.

Such comments clearly delighted Livingstone, who before leaving with Chavez for lunch smiled and told the president that he had views on Bush "not too dissimilar from yours."

The left-wing mayor, who once described Chavez as "the best news out of Latin America in many years," will no doubt take pleasure in embarrassing Blair, with whom he has a distinctly uneasy relationship.

Speaking alongside Chavez at a rally Sunday, he pledged: "Londoners stand with you, not with the oil companies and the oligarchs."

A Foreign Office spokesman told United Press International that Chavez's visit was a private one and that the government had received no requests for meetings with officials. Britain maintained a "constructive" relationship with Venezuela, he said.

The U.S. Embassy in London declined to comment on the visit or Chavez's comments.