The BBC's top executive resigned this morning (NZ time) after the prestigious broadcaster's marquee news magazine wrongly implicated a British politician in a child sex-abuse scandal.
The resignation plunges the network into further uncertainty amid a controversy that exploded after it decided not to air similar allegations against one of its own stars who police now say was one of nation's worst pedophiles.
In a brief statement outside BBC headquarters, George Entwistle said he decided to do the "honourable thing" and step down after just eight weeks in the job.
"When appointed to the role, with 23 years' experience as a producer and leader at the BBC, I was confident the trustees had chosen the best candidate for the post, and the right person to tackle the challenges and opportunities ahead. However the wholly exceptional events of the past few weeks have led me to conclude that the BBC should appoint a new leader," he said.
It was a rapid about face for Entwistle, who earlier Saturday had insisted he had no plans to resign - despite growing questions about his leadership and the BBC's integrity in wake of the scandals.
John Whittingdale, chairman of the Britain's Commons Culture, Media and Sport Committee, said Entwistle had no choice but to go, as recent events had left the impression that the BBC's management has "lost their grip" of the organisation.
"I think that what has happened in the last few days has immensely weakened his authority and credibility," Whittingdale said in response to the resignation. "It would have been very difficult for him to continue in those circumstances."
Entwistle assumed the mantle as head of the BBC just two months ago from Mark Thompson, who was appointed chief executive of The New York Times Co in August and is due to take up the post next month.
Last month he was faced with his first crisis due to the growing scandal revolving around Jimmy Savile, the renowned BBC TV host who died last year and who is alleged to have sexually abused numerous young people.
In addition to the troubling possibility that Savile may have used his position - and BBC premises - to carry out assaults, the scandal further jolted BBC because its "Newsnight" investigative program, decided to shelve its own report into allegations against Savile.
That decision prompted deep soul-searching at the venerated broadcaster and assurances from Entwistle that he would get to the bottom of the decision.
But the furore was reignited when the same program aired a report on November 2 about alleged sex abuse in Wales in the 1970s and 1980s. During the program, victim Steve Messham claimed he had been abused by a senior Conservative Party figure.
The BBC didn't name the alleged abuser, but online rumours focused on Alistair McAlpine, a Conservative Party member of the House of Lords. On Friday (Saturday, NZ time), he issued a fierce denial and threatened to sue.
Messham then said he had been mistaken about his abuser's identity and apologised to McAlpine, prompting fury over the BBC's decision to air the report, the suspension of investigative programs at "Newsnight" and mounting questions over Entwistle's leadership.
Enwistle had insisted he was not aware of the program before it was broadcast - saying in hindsight he wished the matter had been referred to him.
But that stand drew incredulity from politicians and media watchers wondering how he could have allowed a second botched handling of a high-profile child sex-abuse story so soon after the broadcaster was pitched into crisis over allegations against its late TV host Jimmy Savile.
The BBC Trust's chairman, Chris Patten, called Saturday "one of the saddest evenings of my public life" but praised Entwistle's "honour and courage" in tendering his resignation.
"At the heart of the BBC is its role as a trusted global news organisation, and as the Editor-in-Chief of this organisation, George has very honourably offered us his resignation because of the unacceptable mistakes and the unacceptable shoddy journalism which has caused so much controversy," Patten said.
British Culture Secretary Maria Miller welcomed the resignation, calling it "regrettable but the right decision."
"It is vital that credibility and public trust in this important national institution is restored. It is now crucial that the BBC puts the systems in place to ensure it can make first class news and current affairs programs," she said.