The government has agreed to release details of dozens of conversations between Tony Blair and George Bush about the invasion of Iraq, in a significant victory for Sir John Chilcot's probe.
The Iraq inquiry had been in deadlock with the Cabinet Office over its wish to see records of critical discussions between the two men responsible for the 2003 invasion of Iraq made public.
Officials had argued that publishing the documents would make it much harder for future prime ministers to do their job because of the fear that similar revelations could damage their future reputations.
But Chilcot has now written to Cabinet secretary Sir Jeremy Heywood making clear details of over 200 Cabinet and Cabinet committee meetings will be released - including the minutes of the most significant.
Rather than publishing records of discussions between Blair and Bush in their entirety only specific quotes or "gists of the content" will be released.
"Consideration will be based on the principle that our use of this material should not reflect President Bush's views," Chilcot wrote in a letter to Heywood confirming the deal.
"We have also agreed that the use of direct quotation from the documents should be the minimum necessary to enable the Inquiry to articulate its conclusions.
"It is not yet clear how long detailed consideration of these gists and quotes will take but the Inquiry and the government should work to complete this task as soon as possible."
MPs have become deeply frustrated at the delay in the publication of the report's final conclusions, which were expected several years ago. The Commons' public administration select committee has begun proceedings to investigate the deadlock.
The threat of appearances before Bernard Jenkin's committee may have helped break the deadlock, allowing the unprecedented disclosure of material despite what the inquiry called "issues of long-standing principle".
A delay remains inevitable, however. All the principle parties, including Blair, must be notified in order to give their responses to the report before its final conclusions are made public.