Physician to the King (or Queen, as appropriate) is a title (as postnominals, KHP, QHP) held by physicians of the Medical Household of the Sovereign of the United Kingdom. Part of the Royal Household, the Medical Household includes physicians, who treat general conditions, and extra physicians, specialists who are brought in as required.
In 1973, the position of Head of the Medical Household was created. The occupant of that position is also a Physician to the King.