By politics.co.uk staff
Desmond Tutu has pulled out of a leadership conference after refusing to share a platform with Tony Blair because of the 2003 invasion of Iraq.
The archbishop cited Blair's "morally indefensible" decision to participate in the US-led military invasion to oust Saddam Hussein from Baghdad "on the basis of unproven allegations of the existence in Iraq of weapons of mass destruction", according to his office.
Tutu's decision to pull out from the Discovery Invest Leadership Summit 2012, which also features speeches by former Tesco chief Terry Leahy, Russian dissident Garry Kasparov and former New York City mayor Rudy Giuliani, will prove embarrassing for Blair.
The ex-PM's office said he was sorry that the archbishop was pulling out from an event which had been "fixed for months" in their diaries. Blair's aides pointed out that "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 - such disagreement is part of a healthy democracy," the spokesperson said.
"As for the morality of that decision we have recently had both the memorial of the Halabja massacre where thousands of people were murdered in one day 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."
The local Muslim political party Al Jama-ah is set to protest at Blair's attendance at the Johannesburg summit, the Herald Sun newspaper reported.