The former UN spokesman in Sri Lanka Gordon Weiss tells Channel 4 News that a leaked UN report into "credible allegations" of war crimes represent Sri Lanka's "Srebrenica moment".
Weiss told Channel 4 News they were at the "hard edge of humanitarian work" and were prevented from reaching the area by the Sri Lankan government. There "no foreign observers there to observe what was happening", Weiss said.
Weiss, who left the UN to write a book on Sri Lanka's civil war said he was "part of that structure" and "I bare my portion of the responsibility and blame for that."
He said that culpability rested on a "a fairly narrow range of senior leaders in Sri Lanka".
The Sri Lankan government, who received a copy of the report, said they found the report "fundamentally flawed in many respects" and that it was based on biased material.
In a statement on their website the Sri Lankan government said that it will respond in due course.
Weiss said however that he thinks ultimately there will be a war crimes tribunal:
"I think it will be very difficult for any of the great powers to ignore now what went on in Sri Lanka.
"It may well have been swept under the carpet, but this panel report has reversed the tide and I think we will see action.
"I believe we will eventually see a war crime process."
"This is Sri Lanka's Srebrenica moment, in fact it's a Srebrenica moment for the rest of the world."