Tony Blair has ducked calls for him to sanction the release of his exchanges with George Bush in the run-up to the Iraq war.
Grilled by reporters on the Chilcot Inquiry after a speech on Europe, the tight-lipped former Prime Minister said: "In respect of Chilcot, I'll leave that for another day."
Campaigners have criticised as a whitewash the decision to limit publication to "quotes or gists", and the mother of one soldier killed in the conflict said she was "sickened".
Years of negotiations over the publication of the "vital" material, which includes 25 notes from Mr Blair to the then US President and more than 130 records of conversations between them, is understood to have been behind long delays in publication of the report into the invasion.
Sir John said at the weekend that withholding the details would "leave suspicions unresolved and those suspicions will fester and maybe worsen".
He said there were "strict rules" preventing the current Government from getting involved and insisted it was up to Labour or Mr Blair to allow the papers to be released.
Rose Gentle, whose 19-year-old son Gordon was killed in Iraq in June 2004, said she was "sickened" by the decision to publish only selected sections and believed Mr Blair would "walk away from it with a smile on his face".