Global Policy Forum

By Colin Brown, Kim Sengupta and Andrew Grice

Downing Street admitted yesterday that MI6 embarked on an unprecedented cover-up after it withdrew intelligence supporting the Government's dossier on Saddam Hussein's weapons of mass destruction because it was unreliable.

In an astonishing admission after the disclosure of the cover-up in yesterday's Independent, Tony Blair's official spokesman said MI6 decided not to tell the Hutton inquiry - set up to investigate the death of the government scientist David Kelly - that crucial intelligence on Saddam's chemical and biological weapons was unsound. The security services, he said, felt it was "too sensitive'' to be made public. The head of MI6, Sir Richard Dearlove, also decided not to tell Mr Blair. The Prime Minister's spokesman said Mr Blair only became aware of the withdrawal of the intelligence as a result of the inquiry by Lord Butler of Brockwell, which was delivered three days ago.

Senior sources close to last year's Hutton inquiry said they were unaware that crucial intelligence had been withdrawn, and had this been known, a number of government witnesses would have faced questions about the matter. The sources insisted that the fact that intelligence had been withdrawn by MI6 was not revealed to Lord Hutton either orally or in written evidence. After the death of Dr Kelly, Mr Blair asked Lord Hutton to conduct an inquiry. Mr Blair's official spokesman said on 21 July last year: "The important point is that we have said that he will have whatever papers and people he needs."

The inquiry began on 11 August. Giving evidence, the Prime Minister, Sir Richard Dearlove and John Scarlett, the head of the Joint Intelligence Committee, all failed to mention the withdrawal of intelligence. All three insisted that intelligence from agents in Iraq was believed to be reliable. Downing Street insisted yesterday that the first time Mr Blair knew about the discredited intelligence was in the Butler report. And the reason Mr Scarlett had not mentioned it, when giving evidence two months after MI6 had withdrawn the intelligence, was that "the validation process was still ongoing".

Senior MPs said Downing Street's comments had all the hallmarks of a damage limitation exercise. Had Mr Blair known, he would face fresh allegations of misleading Parliament on Tuesday when he opens a debate on the Butler report. Downing Street gave three reasons for not telling the Hutton inquiry: it was not relevant to the investigation into Dr Kelly's death; it was only one element in the chemical and biological weapons "picture"; and, because validation of the intelligence and its source was continuing, it was too sensitive to make public. "Lord Hutton was not misled. He saw everything that was relevant to his picture," said Mr Blair's spokesman.

Two parliamentary committees were also kept in the dark and last night there was a backlash as MPs claimed they had been misled. The Prime Minister's Intelligence and Security Committee (ISC) will meet next week to decide whether to hold a fresh inquiry into the disclosures in the Butler report. A senior member of the ISC said: "We were not told about this. We were shown some of the evidence. I think it is a real issue of concern that the SIS [Intelligence and Security Committee] have done this without telling us." Lord King, a former chairman of the ISC, said: "It was for Lord Hutton to decide whether it was not relevant. "

The intelligence services also failed to tell the Commons Foreign Affairs Committee, which investigated the death of DrKelly, that it had "withdrawn'' the crucial intelligence. The decision to withdraw the intelligence was taken in July, last year, the same month that Mr Blair was forced to call the Hutton inquiry into the circumstances surrounding the death of Dr Kelly, who was named as the source for reports that the dossier had been "sexed up'' by Downing Street.

Exactly a year ago, Dr Kelly went for his fateful walk in the woods. Mr Blair is finding it impossible to draw a line under the events that his death set in train.