Lord Hall said that remaining in the position, which he has held for less than a year, would be “a distraction to an institution I care deeply about”.
The BBC has faced questions about the conduct of its former boss since an official inquiry found that broadcaster Martin Bashir used “deceptive” methods to secure his 1995 interview with Princess Diana – including why Mr Bashir was rehired in 2016 despite longstanding allegations of deceit, and whether Lord Hall was involved in the rehiring process.
Lord Hall, who was director-general of the BBC between 2013 and 2020 and oversaw news and current affairs in the 1990s, was strongly criticised in Lord Dyson’s report for overseeing a “woefully inadequate” internal inquiry into Mr Bashir after his Panorama interview aired.
Tim Suter, who was also involved in the investigation which exonerated Mr Bashir, resigned from his role at Ofcom on Friday.
“I have today resigned as chair of the National Gallery,” Lord Hall said in a statement.
“I have always had a strong sense of public service and it is clear my continuing in the role would be a distraction to an institution I care deeply about.
“As I said two days ago, I am very sorry for the events of 25 years ago and I believe leadership means taking responsibility.”
The National Gallery said it “understands and respects” Lord Hall’s decision to step down.
Sir John Kingman, deputy chair of the National Gallery board of trustees, said: “Tony Hall has been doing a superb job as chair of the National Gallery, where he is much respected and liked.
“The gallery is extremely sorry to lose him, but of course we entirely understand and respect his decision.”
Earlier this week, MP Julian Knight, chair of the Digital, Culture, Media and Sport Committee, demanded assurances from the BBC in the wake of Lord Dyson’s findings.
“There are serious questions still left to answer,” he said. “Why was Martin Bashir rehired, with the BBC knowing what they knew?
“I want to know how the BBC can reassure the committee that there could be no repeat of the serious failings that have been highlighted by the Dyson report.”
In a BBC interview, former BBC News director James Harding sidestepped questions about whether Lord Hall was involved in Mr Bashir’s rehiring.
“What I was saying is that BBC News hired Martin Bashir, and so the responsibility for that sits with me,” he said.
Lord Dyson’s report concluded that Mr Bashir used “deceptive” methods while securing an interview with Princess Diana, including showing forged documents to her brother Earl Spencer.
Mr Bashir has apologised for this, but maintains that the princess would have agreed to the interview regardless of his forgery.
Princess Diana famously said during the interview with Mr Bashir that there were “three people” in her marriage to Prince Charles – a reference to Camilla Parker Bowles, who is now married to the Prince of Wales.
Dr Gabriele Finaldi, director of the National Gallery, said that Lord Hall had been a “pleasure” to work with.
“He has demonstrated extraordinary commitment to the gallery and it has been a great pleasure to work closely with him as we have faced the challenges of Covid and as we prepare to mark the gallery’s bicentenary in 2024,” he said.