Former BBC Director General George Entwistle resigned amid tough questions over the network’s handling of an escalating child sex abuse scandal. (Peter Macdiarmid/GETTY IMAGES)

With the BBC facing its deepest crisis in years, trustees of the global broadcaster began a desperate search on Sunday for a new director general, a day after its former chief resigned amid tough questions over the network’s handling of an escalating child sex abuse scandal.

The search kicked off as government officials called on the BBC to regain the public’s confidence in one of the world’s biggest broadcasters.

Speaking on BBC television, Theresa May, Britain’s home secretary, said that the corporation needed to restore “trust and credibility” to rebuild itself as a “renowned national institution” and a “worldwide brand.”

On Saturday night, George Entwistle, 50, abruptly stepped down as director general after a BBC broadcast that falsely accused a former Conservative politician of child abuse.

Chris Patten, chairman of the BBC Trust, the broadcaster’s governing body, said on the BBC Sunday that Entwistle resigned “extremely honorably” after taking responsibility for “awful journalism” in a program by BBC’s “Newsnight,” a prestigious current affairs program. Patten said that the broadcaster hoped to have someone new at the helm within weeks. In the meantime, Tim Davie, 45, formerly the head of audio and music, has stepped in as acting chief.

Patten also suggested the BBC, an organization with 22,000 employees, needed a “thorough, structural, radical overhaul.”

The BBC has had a difficult few months. Within days of taking over from Mark Thompson, who on Monday begins work as the new chief executive of the New York Times Co., Entwistle began dealing with a scandal over the late Jimmy Savile, a former star presenter on the BBC. Last year, after looking into allegations that Savile had sexually abused children, some of them at the BBC headquarters, “Newsnight” shelved its investigation, reportedly due to lack of evidence. ITV, a rival broadcaster, ran a damning exposé last month. Police have now said that Savile may have abused more than 300 victims.

Within weeks, “Newsnight” was embroiled in a new controversy after it aired an interview on Nov. 2 with Steve Messham, who asserted that he was sexually abused at a care home in North Wales. Although “Newsnight” did not name names, it said that the alleged abuser was a prominent figure in Margaret Thatcher’s government. The name of Alistair McAlpine, a former treasurer for the Conservative Party, soon appeared online. On Friday, Messham retracted his claims, saying it was a case of mistaken identity.

Entwistle’s position arguably became untenable following a ferocious grilling on Saturday morning by BBC presenter John Humphrys, sometimes called the “Rottweiler” of radio news. Entwistle, who had already been dubbed “Incurious George” by the British press, admitted that he wasn’t aware of the serious allegations in the “Newsnight” program before it aired. David Mellor, a former cabinet minister, said after the interview that Entwistle came across as “so out of touch, it made me think Winnie the Pooh would have been more effective.”

On Saturday evening, after only 54 days on the job, Entwistle resigned. The mounting criticism leveled against the BBC comes at a time of deep uncertainty for the British press as it nervously awaits a report by Brian Leveson, a judge who led an inquiry into press standards following the phone hacking scandal last year that rocked the British establishment. His report, expected later this month, could have a profound impact on how the print press is regulated.

John Whittingdale, the chairman of the government’s culture, media and sport committee, told the BBC on Sunday that “people need to take responsibility” for the decision to broadcast the erroneous “Newsnight” episode. “So, potentially it may require other people to resign,” he said.