Photo: Elke Wetzig/Wikipedia

File photo: Desmond Tutu. Tutu's withdrawal from the Discovery Leadership Summit may prove a critical moment in the build-up of pressure on international governments and the institutions of international justice to pay attention to the movement calling for Blair's prosecution for war crimes.

Archbishop Emeritus Desmond Tutu has withdrawn from participating in a leadership summit in Johannesburg later this week.

"The Archbishop has spent considerable time over the past few days wrestling with his conscience and taking counsel from trusted advisers with respect to his attendance at the event," the Archbishop's office wrote to the event organisers today.

"Ultimately, the Archbishop is of the view that Mr Blair's decision to support the United States' military invasion of Iraq, on the basis of unproven allegations of the existence in Iraq of weapons of mass destruction, was morally indefensible. The Discovery Invest Leadership Summit has leadership as its theme. Morality and leadership are indivisible. In this context, it would be inappropriate and untenable for the Archbishop to share a platform with Mr Blair.

"The Archbishop greatly regrets inconveniencing and disappointing the organisers and participants of the Discovery Invest Leadership Summit."