A royal author has said an investigation is under way into how the Dutch version of his new book named two senior members of the British royal family alleged to have discussed the skin colour of the Duke and Duchess of Sussex’s unborn son.

In an edition that has now been withdrawn from bookshelves, King Charles and the Princess of Wales were named as taking part in conversations about Prince Archie before his birth, according to allegations in the book that have been broadcast on TV programmes in the UK and the Netherlands.

The book claims conversations about Archie related to how it opened up discussions about whether there was “unconscious bias” in the royal family.

Scobie said: “Firstly, I have never used the racist word in this subject. Even the book makes it very clear we are talking about unconscious bias here.

“We’re talking about a conversation that was raised about the colour of Archie’s skin, that they called “concerns”. For me it was important to get to the bottom of that; why was it not covered ever again, why did the Sussexes never talk about it, what happened behind the scenes? The palace said it was being dealt with privately. Was it?”