Alastair Campbell denied today that he had sought to "beef up" the Government's now notorious dossier on Saddam Hussein's supposed weapons of mass destruction (WMD).
Giving evidence to the Iraq Inquiry, Tony Blair's former communications director said he had given "presentational" advice on the drawing up of the document published in September 2002.
But he insisted that he never sought to override the intelligence judgments of the report's author - chairman of the Joint Intelligence Committee (JIC) Sir John Scarlett.
"At no time did I ever ask him to beef up, to override, any of the judgments that he had," he said.
"At no point did anybody from the prime minister down say to anybody within the intelligence services 'You have got to tailor it to fit this judgment or that judgment'. It just never happened.
"The whole way through, it could not have been made clearer to everybody that nothing would override the intelligence judgments and that John Scarlett was the person who, if you like, had the single pen."
Mr Campbell said Sir John insisted throughout that he was "100% in charge" of the process of compiling the dossier.
But, early in September 2002, Mr Campbell confirmed that he chaired two meetings in No 10 to discuss the publication of the report.
"John Scarlett said to me 'This is a document the prime minister is going to present to Parliament, there are massive global expectations around it, and I need a bit of presentational support', and that is what I gave him," Mr Campbell said.
"I think it entirely not just appropriate but absolutely necessary that I should have done that. I was the person who was charged by the prime minister to advise him on all the presentational aspects to do with the dossier."
Mr Campbell insisted that the dossier had never been intended to make the case for war against Saddam, but was simply meant to show why Mr Blair was becoming increasingly concerned about his WMD programme.
Mr Campbell said he drafted Mr Blair's foreword to the dossier, in which he said that intelligence showed "beyond doubt" that Iraq had chemical and biological weapons, although the prime minister had "almost certainly" re-written it.
He rejected Sir John's earlier evidence to the inquiry that he did not believe that he could have changed the foreword as it was a "political statement" by Mr Blair.
"If John Scarlett or any of his team had had any concerns of real substance about the foreword, then they know they could have raised those directly with the prime minister," he said.
"I don't believe that if any of the JIC thought that the foreword in any sense over-stated the case to a degree that would impact the work that they had done - hit its credibility - they didn't feel they had the opportunity to say something."
Mr Campbell denied any knowledge of suggestions Britain attempted to "align" the dossier with American statements.
"If that was going on at the intelligence level, I have no idea but, in terms of my role in relation to the dossier, I had nothing to do with it whatsoever," he said.
He said the claim that Iraq could launch a WMD within 45 minutes was not "that big a deal" within the dossier.
And he denied the Government had been involved in a "sexing up game" in exaggerating the threat.
"I don't think we were ever saying, 'look Saddam Hussein has got these weapons and can whack them off to Cyprus in 45 minutes'," he added.
But he accepted the case could have been presented in a better way.
"Could it have been clearer? Obviously," he said. "You can go back with the benefit of hindsight and re-write every single bit but I'm simply saying to you that (the 45-minute claim) was not that big a point within the overall presentation of the case that the prime minister was putting at the time."
However, he stressed he stood by "every single word" of the dossier.
"I defend every single word of the dossier, I defend every single part of the process," he said.
"I think it was an attempt by the prime minister and the Government to engage the public properly in trying to understand why the prime minister's thinking was developing as it was."
Sir Roderic Lyne, a member of the inquiry panel, asked Mr Campbell why Mr Blair referred to Iraq's WMD programme as "active, detailed and growing" when he addressed Parliament in September 2002.
Previously, the threat had been described as "current, serious and credible".
Sir Roderic said there did not appear to be evidence to back up the suggestion.
But Mr Campbell said the dossier had referred to a "step change" in the programme.
He said: "That was the judgment at the time that he (Mr Blair) was led to make."
Mr Blair saw the threat from Iraq as "unique", said Mr Campbell.
"The prime minister did see Iraq as a unique threat, in part because of its history and its use of chemical weapons, in part because of the means it had deployed to obstruct the United Nations to conceal the weapons programme," he said.
"He did see that as a growing threat."
Mr Campbell admitted that a second intelligence dossier published in February 2003, which also included material taken from a journal on the Middle East, had been a "mistake".
He said the intention had been to expose Saddam's efforts to undermine the UN weapons inspections process in the light of new intelligence from MI6.
However when it became known how it was put together - leading it to be dubbed the "dodgy dossier" - he acknowledged it was damaging to public trust.
"That did not help, let's put it that way," he said. "That was a really difficult episode."
Mr Campbell said Clare Short, then International Development Secretary, should have been involved in discussions over handling post-war Iraq in an "ideal world".
But he said there were concerns information "would get out into the public domain that we did not want to get into the public domain".
"I think in an ideal world the Secretary of State for International Development would, should and could have been involved in all those discussions," he said.
He added: "It was no secret that she was very difficult to handle at times. I think sometimes the military found her approach to them difficult to deal with."
Reflecting on the conflict, Mr Campbell said it could "almost certainly" have been done differently but added he was proud of his role.
"Could things have been done differently? Almost certainly," he said.
"You can go back over it but I think, on the big picture, the leadership that he (Mr Blair) showed, the leadership that the British Government showed on this issue, I was privileged to be there and I'm very proud of the part I was able to play."
The hearing was adjourned until tomorrow.