The Duchess of Sussex formally complained to ITV about Piers Morgan before the Good Morning Britain co-host quit, the PA news agency understands.

Morgan left the breakfast show after an on-air row with a colleague who criticised him for “continuing to trash” the duchess, after earlier this week saying he “didn’t believe a word” of Meghan’s Oprah Winfrey interview.

PA understands the duchess’ concern was not about the personal attacks on the validity of her racism allegation made against the royal family, or her claims she was not supported by the institution when experiencing suicidal thoughts.

The complaint is understood to focus on how Morgan’s comments may affect the issue of mental health generally and those attempting to deal with their own problems.

ITV bosses had asked Morgan to apologise to the duchess during Tuesday’s show but he refused, the Telegraph reported.

The development follows Buckingham Palace’s statement, saying that the issues raised in Harry and Meghan’s bombshell interview, especially over race, were “concerning” and would be addressed by the Queen and her family privately.

The royal family said it was taking “very seriously” the couple’s shocking allegation that a member of the family – not the Queen or Duke of Edinburgh – raised concerns about how dark their son Archie’s skin tone might be before he was born.

The royals appear to be at odds over the version of some events described by the Sussexes as the statement highlighted how “some recollections may vary”.

But the sympathetic tone of a Buckingham Palace statement suggests a reconciliation through dialogue in private is the aim.

Asked to respond to Buckingham Palace’s statement about the interview, a spokesman for the Sussexes said they would not be commenting any further.

Morgan criticised Meghan as he co-hosted Monday’s Good Morning Britain show, and after a clip aired of the duchess discussing her struggles with mental health and the monarchy’s knowledge of them, he said: “I’m sorry, I don’t believe a word she says.

“I wouldn’t believe her if she read me a weather report.”

Morgan walked off the set on Tuesday after an on-air clash with his colleague, Alex Beresford.

Mind, a leading mental health charity, led the way in criticising Morgan’s comments.

It said in a tweet posted earlier this week it was “disappointed and concerned to see Piers Morgan’s comments on not believing Meghan’s experiences about suicidal thoughts”.

The charity added: “It’s vital that, when people reach out for support or share their experiences of ill mental health, they are treated with dignity, respect and empathy.”

Morgan faces an Ofcom investigation after the regulator received 41,000 complaints following his comments on Monday.