The Chilcot report into the 2003 Iraq conflict was delayed further;even though, it was due to have been published three years ago, the Guardian newspaper reported Friday.
The report now threatens to haunt UK politics ahead of the 2015 election, the newspaper added.
The Chilcot inquiry was set up in 2009 and has cost over 9 million pounds so far - and it will unlikely be published until next year.
The inquiry is expected to contain damning criticism of the way former UK premier Tony Blair and his close advisers led Britain into war against Iraq, the publication said.
The delay is likely to raise more controversy in the light of the present crisis in Iraq which "threatens to perpetuate deep divisions and violence in the oil-rich country", the paper commented.
Government sources here suggest the latest delay in the long-awaited report is the result of continuing disputes over criticisms the Chilcot panel plan to make of Blair and other ministers and advisers involved in the decision to invade Iraq, it added.
Chilcot announced last month that after years of heated disputes with successive cabinet secretaries, and discussions with Washington, he had agreed to a settlement whereby summaries, and "the gist", of more than a hundred records of conversations between Blair and former US president George Bush in the runup to the invasion, and of records of 200 cabinet discussions, would be published, but not the documents themselves.
Chilcot has described the content of the documents as "vital to the public understanding of the inquiry's conclusions".
In a letter to Sir Jeremy Heywood, the cabinet secretary, last month, Chilcot said "detailed consideration" of the information he has requested had begun, adding "it is not yet clear how long that will take." Philippe Sands, lawyer and professor of law at University College London, said: "How painfully ironic that Britain used force in 2003 when it was manifestly illegal, but will likely and rightly not do so now in response to a request from the government of Iraq, when it would rather more arguably be lawful." Sands, a close follower of Chilcot and earlier inquiries into the invasion of Iraq, added: "The situation in Iraq today is terrible and tragic, but it's a futile exercise to speculate as to the exact connection with decisions taken in 2003. It would be more sensible to reflect on what might be learnt from the mistakes of the past." He continued: "Who exactly is responsible for the delay [in the Chilcot report] is unclear, but it is hard to avoid the suspicion that political considerations might have come into play." Sands described the delay as "rather disgraceful", and told the Guardian that publication of the report should now be delayed until after the election, to avoid it being used as a political tool.
Prime Minister David Cameron said last month he wanted the report by the end of the year.
The Scottish National party has said it should be published before September's referendum on Scottish independence.
The Chilcot inquiry was set up in 2009 and has cost over 9 million pounds so far