That the king can do no wrong, is a necessary and fundamental principle of the English constitution.
Book III, ch. 17: Of Injuries Proceeding from, or Affecting, the Crown. - Commentaries on the Laws of England (1765–1769)
Avalon Project - Blackstone's Commentaries on the Laws of England - Book the Third - Chapter the Seventeenth : Of Injuries Preeceding From, Or Affecting, The Crown[avalon.law.yale.edu]