By Georgie Keate
The government has used a ministerial veto to prevent the publication of the minutes from Cabinet meetings held just before the war in Iraq.
Information commissioner Christopher Graham released a decision notice asking the government to publish the minutes due to the "significant public interest" involved.
He has said he is "disappointed" the government has chosen to continue Labour's secrecy over the lead up to the military action in 2003.
"His view is that the significant public interest in this matter justified an exception to the general rule that such information should not be disclosed before the usual due date for the release of Cabinet material," an ICO spokesperson said.
The veto is part of the 2000 Freedom of Information Act and was first used by Labour justice minister Jack Straw in 2009 to block the same Cabinet minutes in which the war's legality was discussed.
Back then, Straw claimed: "The damage that disclosure of the minutes in this instance would do far outweighs any corresponding public interest in their disclosure."
It is the third time this year it has been used
Details over the lead up to the Iraq war continues to be shrouded in mystery as Sir John Chilcot, the Iraq inqury's chair, told Cameron its report would be delayed by another year.
Graham has announced he will study the attorney general's reasons for the veto and present a report to Parliament in September.
The ministerial veto has received growing criticism that the FOI Act has become "toothless" as governments continue to use it.
Recently, Andrew Lansley's blocked the publication of the NHS 'risk register', a report into the potential negative consequences of the health reforms.
He told parliament "the public interest is best served by officials and ministers being able privately to consider such issues, including any risks".