The reputation of Britain's intelligence establishment will be on the line when Lord Hutton publishes his report later today.

With the continuing failure to find any weapons of mass destruction in Iraq, the subject still has the potential to cause embarrassment for both the prime minister and the intelligence agencies.

And the law lord's investigation has already raised questions about the way in which the government's intelligence dossier on Iraq was compiled.

A central figure in the debate has been Sir John Scarlett, chairman of Whitehall's joint intelligence committee.

He has claimed "ownership" of the dossier and has defended the intelligence that was included in it.

But questions have been raised about his relationship with senior political appointees within Number 10.

Both chief of staff Jonathan Powell and former communications chief Alastair Campbell suggested amendments to the dossier that appeared to strengthen the way in which it was likely to be interpreted.

However, both the joint intelligence committee of MPs and peers and the Commons foreign affairs committee have broadly cleared the officials of inappropriate "sexing up" of the controversial document.

With much focus on the claim that Iraqi WMDs could be launched within 45 minutes, Lord Hutton may also have words of criticism for the failure to correct the impression that this related to battlefield weapons rather than the chemical and biological munitions that the intelligence suggested.

When he gave evidence, Secret Intelligence Service chief Sir Richard Dearlove insisted that the 45 minute claim was "a piece of well sourced intelligence".

But he accepted that given the way in which the point was highlighted in the report, its executive summary and the foreword it was a "valid criticism" to say it was given undue prominence in the dossier.

However, an anonymous witness from the Ministry of Defence's Counter Proliferation Arms Control Department said that a discussion among experts had prompted the conclusion that the 45 minute claim was "not perhaps a statement that ought to be included" in the dossier.