Letter reveals Campbell proposed 11 changes to Iraq dossier

The letter, from Mr Campbell to the foreign affairs select committee, will be seized on as evidence that the Prime Minister’s press chief played a key role in finalising the wording of the document published last September. It reveals that Mr Campbell raised a series of substantial questions about the dossier, which led to some of the claims about the threat posed by Saddam Hussein being re-worded.

However, the letter appears to exonerate him from the crucial allegation that he ordered inserted into the document the claim that Iraq’s missiles could be ready within 45 minutes.

There is also evidence that in four instances, recommendations made by Downing Street were rejected by the security services.

The absence of the 45-minute claim and the fact that all the changes recommended by Mr Campbell were approved by the chairman of the Joint Intelligence Services (JIC), John Scarlett, are likely to be used by Labour MPs on the committee to clear him.

The committee launched the inquiry following allegations made by Andrew Gilligan, a BBC journalist, that No 10 deliberately "sexed up" the dossier in order to exaggerate the menace posed by Saddam and his weapons of mass destruction.

The allegations - vehemently denied by No 10 - have provoked the most bitter dispute between the government and the BBC in living memory and prompted Mr Campbell to make an extraordinary appearance on television last week to defend his reputation.

In his letter to the foreign affairs committee Mr Campbell says the chairman of the Joint Intelligence Services "has ... authorised me to say that it [the dossier] reflected recent intelligence already in the JIC’s classified assessment and that I played no part in the decision to include the intelligence in the dossier".

He also wrote to the JIC, saying: "It went without saying that there should be nothing published that you [Scarlett and the intelligence agencies] are not 100 per cent happy with."

Despite this disclaimer, parts of the letter are likely to be cited as proof there was an attempt to "hype up" the dossier. Among the changes Mr Campbell secured after two days of discussion with Mr Scarlett was the insertion in the summary of range of Iraq’s extended missiles.

In addition, in the passage on Iraq’s dual use chemical and missile bases, he successfully argued for the phrase "could be used" to be replaced with "are capable of being used".

But Mr Campbell’s suggestions were turned down in a number of other areas. For instance, a request for the executive summary to list the allegation Iraq had imported aluminum tubes for its nuclear programme was rejected as there was no firm intelligence this was the case.

In another passage, he questioned why the report said that Iraq had "sought" to require uranium rather than had done so.

The JIC again insisted intelligence reports did not substantiate such a conclusive allegation.