LONDON — Piers Morgan, one of Britain's harshest critics of Meghan, Duchess of Sussex, resigned as co-host of "Good Morning Britain" television show, ITV announced Tuesday, following a flood of complaints to a British media watchdog.

On Monday morning’s broadcast, Morgan said he “didn't believe a word” Meghan told Oprah Winfrey in her interview alleging mistreatment by Buckingham Palace, specifically her assertion that she felt suicidal and was offered no help.

Morgan also questioned whether the comments made about the skin color of biracial Meghan’s unborn child were necessarily racist.

He stormed off the set Tuesday — and quickly returned — after a colleague challenged Morgan over why he seemed to always “trash” Meghan.

An ITV spokesperson said: “Following discussions with ITV, Piers Morgan has decided now is the time to leave Good Morning Britain. ITV has accepted this decision and has nothing further to add.”

Americans may remember Morgan from his talk show on CNN — he took over the time slot previously filled by the veteran host Larry King. From that perch, he took on the U.S. gun lobby and campaigned for stricter gun-control laws. But his CNN show was canceled after ratings declined.

Morgan co-hosted “Good Morning Britain” for six years.

He had morphed into a spokesman for the anti-Meghan crowd, saying things that many won’t — on his show, in his newspaper column and in his fiery Twitter feed, in which he retweets attacks and hurls firebombs at his critics.

His show Monday was filled with criticism of Meghan and Prince Harry, and Morgan contended that their interview with Winfrey had been an insult to Queen Elizabeth II and the institution of the monarchy.

On Tuesday, presenter Alex Beresford challenged him on his animosity toward Meghan.

“I understand you don’t like Meghan Markle. You made it so clear a number of times,” Beresford said. He then said he understood that Meghan had once known Morgan and cut off her relationship with him.

“She’s entitled to cut you off if she wants to. Has she said anything about you since she cut you off? I don’t think she has, but yet you continue to trash her,” Beresford added.

“Okay, I’m done with this,” said Morgan, who then stalked off. Beresford called his behavior “diabolical.”

Morgan returned after a commercial.

Prince Harry and his wife, Meghan, spoke with Oprah Winfrey about turning away from life as senior royals in a wide-ranging interview that aired on March 7. (The Washington Post)

The former tabloid journalist “acts as a lightning rod to those who don’t like Meghan. He has decided to play that role,” said Steven Barnett, professor of media and communications at the University of Westminster.

“He loves the role of hate figure,” Barnett said. “Let’s not forget he’s on a breakfast show that’s keen to attract more viewers and get more ratings.”

Asked whether he thought Morgan’s storming-off was a spontaneous display of real outrage or just great theater, the professor said: “I don’t want to speculate. Let’s just say it generated a lot of interest.”

Morgan was also criticized by Mind, a leading mental health charity, for “comments on not believing Meghan’s experiences about suicidal thoughts.”

The charity said: “It’s vital that when people reach out for support or share their experiences of ill mental health that they are treated with dignity, respect and empathy. We are in conversations with ITV about this at the moment.”

Morgan addressed those concerns Tuesday, saying he had doubts about the veracity of the overall interview but stressing that “mental illness and suicide are extremely serious things and should be taken extremely seriously.

“My real concern was a disbelief frankly — and I’m prepared to be proven wrong on this and if I’m wrong, it is a scandal — that she went to a senior member of the royal household and told them she was suicidal and was told she could not have any help because it would be a bad look for the family.

“If that is true . . . that person should be fired, and the royal family have serious questions that need to be answered,” he said.

Britain’s television watchdog Ofcom announced Tuesday that it had launched an investigation into Morgan’s comments, related to “harm and offense rules.” The Monday edition of “Good Morning Britain” received more than 41,000 complaints.