Archbishop Desmond Tutu has pulled out of international leadership summit because he doesn't want to share a platform with Tony Blair, it emerged yesterday.
The retired archbishop, right, who received the Nobel Peace Prize in 1984 for his campaigning against apartheid, said that he had withdrawn from the event because he believed the former Prime Minister's support for the invasion of Iraq had been "morally indefensible".
Archbishop Tutu's office added: "The Discovery Invest Summit has leadership as its theme. Morality and leadership are indivisible. It would be inappropriate and untenable for the Archbishop to share a platform with Mr Blair."
A spokesman added that it was not a snap decision, saying that the archbishop "thinks and prays and then acts".
Mr Blair and Archbishop Tutu, alongside the chess grandmaster Garry Kasparov, were due to appear at the leadership summit in Johannesburg later this week.
Mr Blair's office said he regretted the decision but highlighted the number of Iraqi civilians who had been killed by Saddam Hussein's chemical weapons.
"Obviously Tony Blair is sorry that the Archbishop has decided to pull out now from an event that has been fixed for months and where he and the Archbishop were never actually sharing a platform.
"As far as Iraq is concerned they have always disagreed about removing Saddam by force.
"As for the morality of that decision we have recently had both the memorial of the Halabja massacre where thousands of people were murdered by Saddam's use of chemical weapons, and that of the Iran-Iraq war where casualties numbered up to a million including many killed by chemical weapons.
"So these decisions are never easy morally or politically".
Archbishop Tutu has long been a critic of Mr Blair's stance on Iraq – even before the invasion.
In 2003 the archbishop said Mr Blair's support for the Bush administration was "mind-boggling".
"I have a great deal of time for your Prime Minister, but I'm shocked to see a powerful country use its power frequently, unilaterally," he said.
After the invasion he called on Mr Blair to apologise for an error of judgement on Iraq.
"How wonderful if politicians could bring themselves to admit they are only fallible human creatures and not God and thus by definition can make mistakes," he said.
The Muslim political party Al Jama-ah has said that it will attempt to arrest Tony Blair for "crimes against humanity" when he arrives in Johannesburg for the summit.