LONDON -- The BBC struggled Monday to contain a spreading crisis over its reporting of a decades-old sexual abuse scandal as two senior executives withdrew temporarily from their jobs following the resignation of the corporation's director general in the worst setback to the public broadcaster's status, prestige and self-confidence for years.
The BBC's website said its director of news, Helen Boaden, and her deputy, Stephen Mitchell, had "stepped aside," the latest moves since a flagship current affairs program, "Newsnight," wrongly implicated a former Conservative Party politician in accusations of sexual abuse at a children's home in North Wales in the 1970s and 1980s.
The BBC management said that while neither Ms. Boaden nor Mr. Mitchell "had anything at all to do with the failed 'Newsnight' investigation" of the politician, Alistair McAlpine, it "believes there is a lack of clarity in the lines of command and control in BBC News" because of an inquiry into a separate "Newsnight" debacle -- the cancellation of a program a year ago into allegations of sexual abuse by Jimmy Savile, a longtime BBC television host who died last year at age 84.
The BBC said the two executives would step aside until the end of that investigation, which is being conducted by Nick Pollard, a former head of the rival Sky News.
The BBC said its head of news gathering, Fran Unsworth, and Ceri Thomas, the editor of the "Today" current affairs radio program, are to fill in for the executives who stepped aside.
Tim Davie, 45, an executive with a background in marketing who is director of the BBC's radio operations, is to serve as the acting director general. In a videotaped interview posted by the BBC, Mr. Davie also said he would take a short period to deliberate.
"I've just got into the job," he said. "I'm going to take a bit of time to look through the recommendations, and then we'll take the disciplinary process through and be fair to those individuals."
He added: "The BBC has lost a director-general in this process. That in itself is very significant, and he has taken responsibility."
Accounts published in Britain's newspapers, citing current and former BBC staff members familiar, said the "Newsnight" team had worked with an independent group, the Bureau of Investigative Journalism at the City University in London, in preparing the Nov. 2 report that wrongly implicated Mr. McAlpine.
The privately funded bureau was founded in 2009 to investigate controversial issues and, in its own words, to provide a "gold standard" for reporting. It has used experienced journalists and students at the university's journalism school, often in conjunction with mainstream media organizations like the BBC, which have paid the bureau for its work.
In a statement, the bureau's board of trustees has said it was "appalled by what appears to be a breach" of standards and that "remedial action will be taken against those responsible."
The bureau's work for the report was led by a former BBC reporter, Angus Stickler, who was loaned to "Newsnight" and worked jointly under a BBC producer and the bureau's own managing editor, Iain Overton, a former BBC producer who resigned Monday.
Several of those involved in the preparation of the "Newsnight" report have been quoted in British papers as saying that errors included not calling Mr. McAlpine for a response and not showing a former child home resident interviewed for the report, Steve Messham, a photograph of Mr. McAlpine to identify him. Mr. Messham has apologized to Mr. McAlpine, tracing the confusion to the police identification of a photograph of a man he identified as his abuser in the early 1990s.
The latest debacle has compounded the problems facing the network since accusations last month against Savile, who was suspected of having sexually abused as many as 300 young people. Critics have accused the BBC of covering up the abuse by canceling a "Newsnight" report on the accusations against him in December.