BBC boss Greg Dyke has conceded the corporation made some errors over the handling of the Iraq dossier story.
Greg Dyke said the BBC may have reacted too quickly to complaints
The director-general made the admission at the first day of the second phase of the Hutton inquiry into the death of weapons expert Dr David Kelly.
His appearance followed that of one of the UK's top spy chiefs, MI6 director Sir Richard Dearlove.
In an unprecedented "public" appearance via audiolink, Sir Richard defended the controversial claim in a government dossier that Iraq could deploy weapons of mass destruction within 45 minutes.
The MI6 director said that had been a "piece of well-sourced intelligence" from an established and reliable source.
He conceded the claim may have been misinterpreted by the public, but said he had not been aware of any unhappiness about it from members of his staff.
Mr Dyke said the BBC had made a mistake in trying to reply too promptly to complaints from former Downing Street press chief Alastair Campbell about a story that the dossier had been "sexed up".
Mr Dyke said that, in hindsight, Mr Campbell's letter should have been passed to the BBC's complaints unit for a full investigation, rather than being dealt with at speed by management.
But Mr Dyke said news bosses had felt they had to react after Mr Campbell staged an "unprecedented" attack, accusing the BBC of bias over its entire coverage of the Iraq war.
Mr Dyke also criticised Today programme correspondent Andrew Gilligan for sending an e-mail, to an MP sitting on a Commons committee investigating broadcasts about the Iraq dossier, which revealed Dr Kelly as the source of a colleague's story.
The BBC chief said: "It is not an acceptable e-mail to send to members of the committee ... he was not in the position to know the source at that stage for [Newsnight correspondent Susan] Watts and nor was he in a position to send this".
Mr Dyke also admitted defending the report without being aware of the wording of one of the broadcasts, nor of an e-mail from Today editor Kevin Marsh, describing it as "flawed".
He also sent his condolences to Dr Kelly's family.
The inquiry has resumed after a 10-day break with Defence Secretary Geoff Hoon, Mr Campbell and Mr Gilligan among witnesses due to be recalled for cross-examination.
On Tuesday, five witnesses are listed - two of whom are to have their statements cross-examined for the first time.
One of the first to face potentially hostile questioning is the deputy chief of defence intelligence, Martin Howard.
He has previously told the inquiry about his involvement in the arrangements for dealing with Dr David Kelly after he admitted talking to a BBC journalist.
Dr Kelly apparently committed suicide after being named in public as the suspected source for Mr Gilligan's report on the dossier.
Ministry of Defence press officer Kate Wilson will also be cross-examined.
The other three witnesses are Detective Constable Coe of Thames Valley Police, pathologist Nicholas Hunt, and a Dr Shuttleworth of the Defence Science and Technology Laboratory (DSTL).
Dr Kelly reportedly said the 45-minute claim had been inserted at the behest of Downing Street against the wishes of intelligence agencies.
But Sir Richard Dearlove said the claim had been based on intelligence "from an established and reliable source equating a senior Iraqi military officer who was certainly in a position to know this information".
Tuesday: Pathologist Mr Hunt; MoD deputy chief defence intelligence Martin Howard
Wednesday: BBC defence correspondent Andrew Gilligan; BBC news director Richard Sambrook
Thursday: MoD personnel director Richard Hatfield; MoD permanent secretary Sir Kevin Tebbit
Monday 22nd: Defence Secretary Geoff Hoon; Downing Street media chief Alastair Campbell
Tuesday 23rd: Prime minister's official spokesman Tom Kelly and Godric Smith; Joint Intelligence Committee chairman John Scarlett; BBC Chairman Gavyn Davies
Wednesday 24th: Dr Kelly's MoD line manager Bryan Wells
Thursday 25th: Closing submissions
He agreed that, in hindsight and with the interpretation the public gave the claim, it could be argued it had been given undue prominence in the dossier.
"But I am confident that the intelligence was accurate and that the use made of it was entirely consistent with the original report."
Explaining the misinterpretation, Sir Richard said the original intelligence report had referred to chemical and biological weapons - which intelligence assessment staff had taken to refer to battlefield weapons.
But he said the 45-minute claim in the dossier had been interpreted by readers as referring to long-range weapons.
Sir Richard was also critical of Dr Kelly, for things he said in his conversation with BBC Newsnight journalist Susan Watts.
"I am shocked to see someone discussing one of the intelligence reports without authorisation. It is a serious breach of discipline," he said.