Tony Blair's key advisers are preparing to face questions at the Hutton inquiry into the death of weapons expert Dr David Kelly.
Number 10 chief of staff Jonathan Powell and David Manning, the prime minister's foreign policy adviser, are due to appear on Monday, while Mr Blair's director of communications Alastair Campbell will give evidence on Tuesday.
The inquiry is examining the circumstances of Dr Kelly's apparent suicide after he was named as the possible source of a BBC report claiming Downing Street "sexed up" Iraq's weapons capability.
Meanwhile Defence Secretary Geoff Hoon has reportedly told colleagues he expects the furore to end his ministerial career.
Mr Hoon telephoned colleagues last week to tell them he anticipated he would have to "fall on his sword" over the affair, according to the Sunday Telegraph.
It emerged at the inquiry last week that Mr Hoon had over-ruled his most senior civil servant to order Dr Kelly to appear before MPs investigating the Iraq weapons row.
THIS WEEK'S WITNESSES
Monday: Pam Teare, Ministry of Defence Press Office head; Jonathan Powell, Number 10 chief of staff; David Manning, Tony Blair's foreign policy adviser
Tuesday: David Manning continued; Alastair Campbell, Number 10 communication director
Wednesday: Sir Kevin Tebbit, MoD permanent secretary; Godric Smith and Tom Kelly, prime minister's official spokesmen
Thursday: Newspaper journalists Nick Rufford, James Blitz, Richard Norton-Taylor, Tom Baldwin; Foreign Affairs Committee chairman Donald Anderson; inquiry secretary Lee Hughes
Pam Teare, head of the Ministry of Defence press office, will be questioned on Monday about how Dr Kelly's name was released to journalists.
The evidence of Mr Blair's close aides, Mr Powell and Mr Manning, is expected to reveal an insight into the inner workings of Downing Street.
Three BBC reporters have told the inquiry Dr Kelly had raised concerns with them about Number 10's use of intelligence on Iraq's weapon threat.
Mr Campbell has been at the heart of the row since BBC reporter Andrew Gilligan said his source had claimed the communications chief was responsible for "transforming" last September's dossier in the week before publication.
Mr Campbell is likely to be asked by the inquiry about his role in preparing the dossier and his involvement in Dr Kelly's name becoming public.
Lawyers acting for the government have flown out to see Mr Campbell at his French holiday home, according to the Observer.
Mr Campbell has always denied influencing the contents of the dossier.
As well as writing several letters to the corporation demanding an apology, he also attacked Mr Gilligan's report when appearing before MPs on the foreign affairs committee and on live television.
The prime minister's spokesman, Tom Kelly, is due before the inquiry on Wednesday.
He apologised after suggesting Dr Kelly was a "Walter Mitty" character.