During the two-hour appearance with Oprah Winfrey, Harry also revealed the problems had ruptured relations with Prince Charles and Prince William, illuminating the depth of the family divisions that led the couple to step away from royal duties and move to California last year.

The palace has not yet responded to the interview, in which Meghan described feeling so isolated and miserable inside the royal family that she had suicidal thoughts and said a member of the family had “concerns” about the colour of her unborn child’s skin.

The family member was not the Queen or Prince Philip, according to Harry, sparking a flurry of speculation about who it could be.

Leaders around the world were asked about the interview.

British Prime Minister Boris Johnson refused to comment, praising the Queen but saying that “when it comes to matters to do with the royal family the right thing for a prime minister to do is say nothing”.

Asked whether US President Joe Biden and his wife Jill had any reaction to the interview, White House spokeswoman Jen Psaki said Meghan’s decision to speak about her struggles with mental health “takes courage” and “that’s certainly something the president believes in”.

The allegations are especially damaging because many observers hoped Harry and Meghan, who is biracial, would help the tradition-bound monarchy relate to an increasingly multicultural nation.

Meghan said that when she was pregnant with her son, Archie, Harry told her the royal family had had “concerns and conversations about how dark his skin might be when he’s born”.

Harry confirmed the conversation, saying: “I was a bit shocked.”

He said he wouldn’t reveal who made the comment.

Meghan acknowledged she was naive at the start of her relationship with Harry and unprepared for the strictures of royal life.

A successful actress before her marriage, she said she bridled at the controlling nature of being royal, squirming at the idea that she had to live on terms set by palace staff. This was compounded by the fact that the staff refused to help her when she faced racist attacks from the media and internet trolls, she said.

The situation became so difficult that at one point, “I just didn’t want to be alive anymore,” Meghan told Winfrey.

But when she sought help through the palace’s human resources department, she was told there was nothing it could do because she wasn’t an employee, Meghan said.

The implications for the interview – which was broadcast Sunday evening in the US and will air in Britain on Monday night – are only beginning to be understood.

The younger royals have made campaigning for support and awareness around mental health one of their priorities. But Harry said the royal family was completely unable to offer that support to its own members.

“For the family, they very much have this mentality of ‘This is just how it is, this is how it’s meant to be, you can’t change it, we’ve all been through it,”‘ Harry said.

In the US, sympathy for the couple poured in.

Tennis star Serena Williams, a friend who attended Harry and Meghan’s wedding, said on Twitter that the duchess’s words “illustrate the pain and cruelty she’s experienced”.

“The mental health consequences of systemic oppression and victimisation are devastating, isolating and all too often lethal,” Williams added.

Britain could be less forgiving once the full interview is broadcast, since some see the pair as putting personal happiness ahead of public duty.