The documents were obtained by The Guardian as part of their ongoing investigation into how the royal family have used an outdated procedure known as the Queen's Consent in order to influence British law.
The documents reveal that although immigrants and people of ethnic minorities were permitted to work in the royal family's staff as domestic servants, in 1968 the Queen's chief financial manager said that "it was not, in fact, the practise to appoint colored immigrants or foreigners" to cleric roles in the royal household.
The documents do not indicate when this practice ended, and royal household records only indicate the racial and ethnic background of staff from the 1990s onwards, making it impossible to know when they repealed this rule.
Buckingham Palace refused to answer questions about the ban and when it had officially been repealed when questioned on the matter by The Guardian.
Due to the Queen's Consent procedure, the Queen is personally exempt from following equality laws which were put into place in the 1970. To this day the exemption makes it impossible for women or people of ethnic minorities to seek legal action due to discrimination they have faced working for the royal household.
The royal family has been under scrutiny for racism and discrimination in recent months due to an interview with Oprah in which Meghan Markle revealed that she had struggled with her mental health during her time in the royal family, and alleged that when she was pregnant with her son Archie, an unnamed member of the royal family had expressed worry about the color of her unborn child's skin.