Political pressure is mounting for the inquiry into the death of weapons expert Dr David Kelly to look at the way the government made its case for war with Iraq.
Dr Kelly was questioned by MPs days before his apparent suicide
The top judge appointed to head the inquiry, Lord Hutton, has insisted that it is for him to decide the scope of his investigation.
But Downing Street said the peer should stick closely to the terms set by Prime Minister Tony Blair "urgently to conduct an investigation into the circumstances surrounding the death of Dr Kelly".
Dr Kelly's body was found in woodland near his Oxfordshire home on Friday.
Conservative home affairs spokesman Oliver Letwin said that doubts over the way intelligence information was used in the build-up to the Iraq war meant that public trust in the government had been undermined.
He said: "We don't think the government should be using this inquiry to limit the
scope of inquiry into the government's actions."
Mr Letwin expressed regret that Mr Blair had opted not to recall MPs and peers from their summer break.
He said only Parliament could give Lord Hutton the power to summon witnesses, take testimony under oath and rule witnesses who failed to co-operate in contempt.
Liberal Democrat leader Charles Kennedy said Lord Hutton will have to touch on "the veracity of intelligence information, the use the government made of that information and any role that Downing Street and the Ministry of Defence may have played in Dr Kelly's name being made public."
An inquest into Dr Kelly's death opened and adjourned on Monday after the coroner said he died as a result of "a haemorrhage due to an incision to his left wrist".
At the weekend the BBC confirmed Dr Kelly had been the main source behind its controversial story which alleged the government had exaggerated the weapons threat posed by Saddam Hussein.
Mr Blair - currently on a visit to China as part of a tour of the Far East - has confirmed he will personally give evidence to the inquiry.
Government officials from Downing Street and the Ministry of Defence, as well as the BBC, are also expected to be questioned.
But Robin Cook, who quit the government over Iraq, said: "I think it would have been much better if the government
had responded two months ago and set up a judicial inquiry into the full facts
of the case then and the history of the last two months might have been very
different if they had."
On Monday Lord Hutton said: "I make it clear that it will be for me to decide as I think right within my terms of reference the matters which will be the subject of my investigation."
Lord Hutton said he aimed "to report as soon as possible".
Just days before he was found dead Dr Kelly had appeared before the foreign affairs select committee - during which he said he did not believe he was the main source for Mr Gilligan's report.
Lord Hutton is expected to look into two crucial points - how Dr Kelly's name was made public, and what exactly he said when he met both Mr Gilligan and fellow BBC reporter Susan Watts to talk about Iraq's weapons of mass destruction.
Following weekend reports, Downing Street said Dr Kelly had been given "a verbal reprimand" about talking to the press by the MoD, but denied any threat being issued to his pension.
Mr Gilligan denied he had "misquoted or misrepresented" Dr Kelly, in a statement on Sunday.
The statement was issued after BBC director of news Richard Sambrook revealed Dr Kelly was the report's principal source, after speaking to his family.
Mr Gilligan's report said "a senior official" had told him the claim that Saddam Hussein's "military planning allows for some of the weapons of mass destruction to be ready within 45 minutes of an order to use them" had been "included in the dossier against our wishes because it wasn't reliable".
On Sunday, Mr Gilligan said Dr Kelly had "expressed very similar concerns about Downing Street interpretation of intelligence in the dossier and the unreliability of the 45-minute point" in both a meeting with him and a separate interview with Ms Watts for Newsnight.
'Respect and restraint'
Mr Sambrook said the corporation believed it correctly interpreted and reported the information obtained from Dr Kelly during interviews.
On Monday's Today programme former cabinet minister Peter Mandelson said the BBC governors had made a "crass error" in investing all the "authority and credibility" of the BBC in defending the original report.
On the same programme, Clare Short said the row with the BBC was a "distraction" and that the questions over Dr Kelly's death were a separate question "from the main question of how we got to war with Iraq".