Not extraordinary. Virginia was legally a British colony in 1775 when Patrick Henry made his speech about liberty or death.
There was nothing in English law that recognized slavery as an institution. It was tolerated in the colonies but not in Britain. This was settled definitively by the Somerset case, 1772.
https://en.wikipedia.org/wiki/Somerset_v_Stewart
Slavery was finally abolished in the British colonies (not including Virginia!) in 1834.
"The Royal African Company (RAC) was an English mercantile (trading) company set up in 1660 by the royal Stuart family and City of London merchants to trade along the west coast of Africa.[1] It was led by the Duke of York, who was the brother of Charles II and later took the throne as James II. It shipped more African slaves to the Americas than any other company in the history of the Atlantic slave trade.[2][3]"
https://en.wikipedia.org/wiki/Royal_African_Company
I'm guessing next you will tell us Britain had nothing to do with the Opium Trade?