The Catholic faith of former British prime minister Tony Blair was pitted against the atheism of journalist Christopher Hitchens during a high-profile debate in Toronto on Friday night, as the two sparred about religion's place in the modern world.

In his opening salvo, Hitchens, who has written that religion is "poison," said that organized religion has been a largely negative factor in humanity and has contributed to many destructive conflicts.

"Is it good for the world to worship a deity that takes sides in wars and human affairs?" Hitchens asked during the event, which was part of the Munk Debates.

But Blair responded by saying that taking away religion wouldn't mean the end of wars.

"I agree in a world without religion, that the religious fanatics may be gone, but I ask you 'would fanaticism be gone?"' Blair pondered.

"The 20th century is a century scarred by visions that had precisely that imagining in their vision and at their heart and gave us Hitler, Stalin and Pol Pot."

Plenty were eager to hear the men argue: the 2,600 tickets were snapped up in hours. Some of the tickets, which have a face value of $20 to $80, are reportedly being sold on Craigslist for $500.

Indeed, the debate is likely the most anticipated event in the series' history. Thousands of others from around the world paid $4.99 to view the event, which was be streamed live on www.munkdebates.com.

"In a world of globalization and rapid social change does religion provide the common values and ethical foundations that diverse societies need to thrive in the 21st century?" the Munk Debates website asks.

"Or, do deeply held religious beliefs promote intolerance, exacerbate ethnic divisions, and impede social progress in developing and developed nations alike?"

Blair is a recent Catholic convert who founded Blair's Faith Foundation in 2008 to promote understanding between religions.

Hitchens, a columnist for Vanity Fair known for his sharp wit is an avowed atheist who has refused to embrace religion despite being stricken with final-stage esophageal cancer.

Despite his illness, Hitchens said that he was up to the challenge of debating a former prime minister. In fact, he arranged his chemotherapy dates around the event, so that he "wouldn't have to let anyone down."

"I arranged my chemotherapy around this so that I wouldn't be demoralized. I'm tired, but I'm not fogged as one can be, so that was the main consideration," he told The Canadian Press.

"This is what I do whether I'm sick or not. (Religion) is still the main argument."

Blair, writes on his Faith Foundation website: "I have always believed that faith is an essential part of the modern world. As globalization pushes us ever closer it is vital it's not used as a force for conflict and division. Faith is not something either old-fashioned or to be used for extremism."

Hitchens, on the other hand, writes in his 2007 treatise, "God is not Great: How Religion Poisons Everything," that organized religion is "violent, irrational, intolerant, allied to racism, tribalism, and bigotry, invested in ignorance and hostile to free inquiry, contemptuous of women and coercive toward children."

The Munk Debates are part of the Aurea Foundation, a charitable organization founded by former Barrick Gold CEO Peter Munk and his wife and Melanie.

Previous Munk Debates have focused on foreign aid, climate change and health care and have included. participants such as Stephen Lewis and actress Mia Farrow.

With files from The Canadian Press