Sir John Scarlett, a former director general of MI6 who was the chairman of the Joint Intelligence Committee (JIC) at the time of the 2003 invasion, told the official inquiry into the Iraq War that Mr Blair's foreword to the document was 'quite separate' from the rest of it.
The document was known as the 'dodgy dossier' because the allegations contained within it that Hussein had WMD's could be deployed at 45 minutes notice were false.
Sir John, who ran the country’s most senior intelligence body and subsequently went on MI6, told how he did not feel able to alter the wording because the former Prime Minister's wording was so political.
He said: "I saw the foreword as quite separate from the text of the dossier itself. The foreword was an overtly political statement by the Prime Minister so it was his wording and his comments throughout," he said. "I didn't see it as something that I would change. My memory of the time is that this was quite clearly something that the Prime Minister wrote." Sir John acknowledged, with hindsight, that it would have been better if the now infamous claim that Saddam had weapons that could be deployed within 45 minutes did not refer to ballistic missiles. But he insisted that it had never been his intention to mislead.
"There was absolutely no conscious intention to manipulate the language or obfuscate or create a misunderstanding as to what they might refer to," he s
Earlier, Mr Scarlett told the inquiry UK intelligence agencies began drawing up detailed assessments of the strengths and weaknesses of Saddam Hussein's regime a year before the invasion.
He revealed the services monitored the 'cohesion' of the regime during the last nine months of 2002.
He said the issues they looked at included: "How stable was the Saddam regime, what were the foundations for its strengths or weaknesses, where relevant, and would it stand up to the kind of pressure which seemed likely to be applied?”
Sir John said: "These were major themes that were under JIC consideration throughout the last nine months of 2002 and then well into 2003 and we did a whole series of assessments."
Asked if he believed the JIC should have looked more closely at the political situation in Iraq and what might happen if Saddam Hussein was no longer in charge, Sir John said: "Of course it's tempting to say in hindsight 'yes' but that is not my honest answer.
"We did do and we knew we had to watch these issues."
The internal situation was monitored and focus placed on the way Saddam might be "thinking and reacting to the situation", he added.
"That was clearly an important requirement and a lot of effort was put in trying to get that right," he said. "Of course it was an exceptionally difficult thing to get right."
Sir John said although Iraq was not a "uniquely" difficult target in terms of intelligence, it was "very difficult" to access information and sources due to the nature of the regime.
He said: "If we are thinking about getting access to sources of really valuable information then achieving that access is very difficult in a highly controlled totalitarian environment which will be backed by strong security agencies and a culture of intimidation and almost certainly fear."
Other problems intelligence teams faced included the lack of a British embassy, he said.
"There were lots of reasons as to why Iraq was a very difficult target. It was difficult to produce intelligence but I don't think I would say it was unique in that way."