Morgan left the ITV breakfast show followng an on-air row with a colleague who criticised him for “continuing to trash” the duchess after his remarks earlier this week that he “didn’t believe a word” of Ms Markle’s interview with Oprah Winfrey.
It has since emerged that the duchess made a formal complaint about the presenter to ITV bosses before he left the show on Tuesday.
But Ms Markle’s 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.
It reportedly focused 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.
Speaking from outside of his London home, Morgan repeated his comments about the duchess: "If I have to fall on my sword for expressing an honestly-held opinion about Meghan Markle and that diatribe of bilge that she came out with in that interview, so be it."
The development follows a statement from Buckingham Palace's saying the issues raised in Prince Harry and Ms Markle’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".
Morgan criticised Ms Markle 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.
His departure from the show has seen nearly £200m wiped off ITV’s market value as of Wednesday, The Guardian reported.
The board of the Society of Editors has said it will "work towards being part of the solution" after the organisation came under fire for issuing a statement, after Meghan and Harry claimed sections of the press were racist, saying the "UK media is not bigoted".
The body, which has almost 400 members in the UK across national, regional and local press, previously said it was "not acceptable" for the couple to make claims of racism in the press "without providing any supporting evidence".
But in a new statement it said its previous comments "did not reflect what we all know: that there is a lot of work to be done in the media to improve diversity and inclusion".
Additional reporting by PA
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