Lady Susan Hussey, who was a close friend of the late Queen and is Prince William’s godmother, is said to have made the comments during a reception at Buckingham Palace yesterday.

The Palace said in a statement that the comments were ‘unacceptable and deeply regrettable’.

Ngozi Fulani, chief executive of Sistah Space, was invited to the event that focused on preventing violence against women.

Ms Fulani, whose charity offers specialist support for women of African and Caribbean heritage affected by abuse, described the conversation as a ‘violation’ and said the experience will ‘never leave me’.

Ms Fulani said a household member first ‘moved my hair to see my name badge’, then challenged her when she said her charity was based in Hackney, saying: ‘No, what part of Africa are YOU from?’

She detailed the full alleged conversation, which she said happened 10 minutes after she arrived, on Twitter, which included the exchange: ‘Where are you from?’

‘Me: “Here, UK”. “No, but what nationality are you?” Me: “I am born here and am British.” “No, but where do you really come from, where do your people come from?” Me: “My people’, lady, what is this?”

‘Oh, I can see I am going to have a challenge getting you to say where you’re from.’

Prince William, in the US for the Earthshot Prize awards, said it was ‘really disappointing’, adding: ‘Racism has no place in our society, these comments were unacceptable. It’s right that the individual has stepped down.’

Buckingham Palace said in a statement: ‘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.’

Mandu Reid, leader of the Women’s Equality Party, tweeted: ‘I was right there. I witnessed this firsthand.

‘We were at an event that was supposed to celebrate our work.’

She said that for people like the woman who made the comments, ‘people like us will never really belong here. Infinite solidarity’.

Ms Fulani told the Mirror that the line of questioning ‘was racism. Through and through. It was prolonged racism.

‘The fact that it was just done in the open in front of people, on a day when we should be working towards violence against women.’

Responding to messages of support online, Ms Fulani wrote: ‘Standing there in a room packed with people while this violation was taking place was so strange, especially as the event was about violence against women.

‘That feeling of not knowing what to do, will NEVER leave me. Almost alone in a room full of advocates.’

She said it was a ‘struggle to stay in a space where you were violated’.

She outlined her distress at not being able to report the incident, saying she felt she could not tell Camilla.

‘There was nobody to report it to. I couldn’t report it to the Queen Consort, plus it was such a shock to me and the other two women, that we were stunned to temporary silence,’ she wrote.

‘I just stood at the edge of the room, smiled and engaged briefly with who spoke to me until I could leave.’

Safe Lives chief executive Suzanne Jacob tweeted it was ‘a horrible thing to happen, and in a space that should have been nothing but love and celebration’ and said she would be raising it with the team who organised for them to be there.