It was discovered that Edward VIII's phone conversations were recorded days before his 1936 abdication on orders of the Home Secretary. In order to control the impending scandal, phone calls from Buckingham Palace and his Windsor residence, Fort Belvedere, were monitored as he decided whether to give up the throne for his mistress, Wallis Simpson.
This shows not only the lack of trust between Edward and his ministers but also what huge lengths the Home Secretary went to keep the controversy quiet after a journalist leaked the story. The papers have been kept in a locked vault for eight decades.
At the time, the Church of England refused to remarry divorcees while their former spouse was still living. If Edward could not be a part of the Church of England, he could not be a leader of England. Ministers gained access to the King's communications to not only keep him honest, but to do damage control of the approaching abdication.