Believe Royal Mail introduced in 1940. First issued postage stanp, the penny black, carried the head of Queen
Victoris. This would have made the penny post royal in my opinion
The Royal Mail traces its history back to 1516, when Henry VIII established a "Master of the Posts". The Royal Mail service was first made available to the public by Charles I on July 31, 1635, with postage being paid by the recipient, and the General Post Office (GPO) was officially established by Charles II in 1660.