A leaked draft of an UN internal report on Sri Lanka concludes that "events in Sri Lanka mark a grave failure of the UN", reports the BBC.

The report, headed by former senior UN official Charles Petrie, points to a “systemic failure” and questions decisions such as the withdrawal of UN staff from the war zone in September 2008, after warning from the Sri Lankan government that it could no longer guarantee their safety.

One member of the UN team that left, Benjamin Dix, claimed to have disagreed with the pull-out, saying:

"I believe we should have gone further north, not evacuate south, and basically abandon the civilian population with no protection or witness. As a humanitarian worker, questions were running through my mind 'what is this all about? Isn't this what we signed up to do?'"

The report says that the situation on the ground was “catastrophic” and points out that:

"many senior UN staff did not perceive the prevention of killing of civilians as their responsibility - and agency and department heads at UNHQ were not instructing them otherwise," going on to describe "a sustained and institutionalised reluctance" among UN personnel in Sri Lanka "to stand up for the rights of people they were mandated to assist".

A Tamil asylum seeker who was formally a school teacher in the war zone told the BBC:

"We begged them, we pleaded with them not to leave the area. They did not listen to us. "If they had stayed there, and listened to us, many more people would be alive today."

The failure of the UN to publicise that the “large majority” of deaths were caused by government shelling is also detailed, with the report saying that the UN should have revealed what was happening to the world and done more to try and prevent it.

The report details that in New York:

"Engagement with member states regarding Sri Lanka was heavily influenced by what it perceived member states wanted to hear, rather than by what member states needed to know if they were to respond".

Not a single meeting was held at the Security Council or any other top UN bodies during the last months of the war.

Frances Harrison, author of Still Counting the Dead, told the BBC:

"The only way now for Ban Ki-moon to restore the UN's tattered credibility on Sri Lanka is to call an independent international investigation into the slaughter of tens of thousands of civilians in 2009".