Americans have a weird way of describing a person racially. It seems if you had ANY ancestor with "non-white" blood you are black. Mostly Americans refer to Megan Markle as "black", she’s not much darker than Prince Harry, a white red-headed English/Scottish blooded person. So she’s not black, she’s American! Her hair is black, and it’s a huge contrast to her skin color.
So when will the UK have a "black Queen", probably when a crown prince goes to Africa on a visit and meets his future wife but do you know that UK had a black queen in past already.
In 1761, Britain’s King George III married a 17-year-old German princess, Charlotte of Mecklenburg-Strelitz. They had many children together. Charlotte would go on to win the British public’s affection due to her loyalty and devotion to the king during his descent into madness. Now, there is one portrait of Charlotte (at a young age) which some see as suggestive that she may have had some African as well as European features.
Charlotte would appear to be the great-granddaughter of Afonso’s mistress, Madragana and because she married George III and bore his children, Charlotte herself is an ancestor of today’s British royal family, including the current Queen of the UK. Ergo, our current Queen Elizabeth II potentially has a 13th century ‘Moorish’ ancestor.
Charlotte herself was black. It simply states that she probably had black ancestors. Some people claim to have traced her ancestry back to an African slave but that slave lived over 500 years before Charlotte so any African ancestry she had would have been pretty diluted by Charlotte’s time.