Archbishop Desmond Tutu has called for Tony Blair and George Bush to be taken to the International Criminal Court in The Hague for their role in the Iraq war.
The Nobel Peace Prize winner accused the former British and US leaders of lying about weapons of mass destruction and said the invasion left the world more destabilised and divided "than any other conflict in history".
He wrote in the Observer that the US and UK-led action to oust Saddam Hussein in 2003 created the backdrop for the civil war in Syria and a possible wider Middle East conflict involving Iran.
He said: "The then leaders of the United States and Great Britain fabricated the grounds to behave like playground bullies and drive us further apart. They have driven us to the edge of a precipice where we now stand - with the spectre of Syria and Iran before us."
As for the call for Mr Blair and Mr Bush to face justice in The Hague, he said different standards appeared to be set for prosecuting African leaders than western ones, and that the death toll during and after the Iraq conflict was sufficient on its own for them to face action.
"On these grounds, alone, in a consistent world, those responsible should be treading the same path as some of their African and Asian peers who have been made to answer for their actions in The Hague."
Archbishop Tutu, a long time critic of the Iraq war, pulled out of a South African conference on leadership last week because Mr Blair was attending.
Mr Blair said: "I have a great respect for Archbishop Tutu's fight against apartheid - where we were on the same side of the argument - but to repeat the old canard that we lied about the intelligence is completely wrong as every single independent analysis of the evidence has shown.
"And to say that the fact that Saddam massacred hundreds of thousands of his citizens is irrelevant to the morality of removing him is bizarre...
"In short this is the same argument we have had many times with nothing new to say. But surely in a healthy democracy people can agree to disagree. I would also point out that despite the problems Iraq today has an economy three times or more in size with child mortality rate cut by a third of what it was. And with investment hugely increased in places like Basra."