A royal aide at the centre of a race row was deployed by the Queen to help Meghan Markle adjust to royal life, a book claims.
It is said that Lady Susan Hussey, who is a godmother of Prince William, was one of two women who worked for the late monarch who were assigned to support Meghan when she first became a working royal.
Lady Susan, 83, was at the Queen's side for more than 60 years as a lady-in-waiting and since the monarch's death had been appointed a lady of the household to assist the King in hosting formal occasions at Buckingham Palace.
However, today she resigned and apologised after allegedly asking a black visitor at Buckingham Palace: "What part of Africa are you from?"
In a Twitter post, Ngozi Fulani, who runs a black women's domestic abuse charity, claims she was questioned about her ethnicity by Lady Susan.
An investigation has been launched and the palace slammed the "unacceptable and deeply regrettable comments".
In former Vanity Fair editor Tina Brown's book The Palace Papers, the author claims that the Queen offered Meghan "the ear of her most senior lady-in-waiting, Lady Susan Hussey" as well as communications aide Sam Cohen "to support the new Duchess’s learning curve".
But she adds that the former lady-in-waiting was also someone Princess Diana "couldn't stand".
Tina writes: "The glaring but unspoken problem was that none of these experienced Palace hands were women of colour.
"As for the lady-in-waiting the Queen had offered for support, what on earth did the eighty-year-old Lady Susan Hussey have of use for a thirty-eight-year-old biracial American actress trying to navigate the treacherous Palace system?
"She hailed from the Jurassic period of court etiquette, and had also been proffered for guidance to Diana (who couldn’t stand her)."
Referring to the incident at Buckingham Palace yesterday, a palace spokesman said: "We take this incident extremely seriously and have investigated immediately to establish the full details.
"In this instance, unacceptable and deeply regrettable comments have been made. We have reached out to Ngozi Fulani on this matter, and are inviting her to discuss all elements of her experience in person if she wishes.
"In the meantime, the individual concerned would like to express her profound apologies for the hurt caused and has stepped aside from her honorary role with immediate effect.
"All members of the Household are being reminded of the diversity and inclusivity policies which they are required to uphold at all times."
