As Britain’s head of state-in-waiting, Prince William will one day receive intelligence reports, and the heir to the throne got a start on such briefings by visiting MI6 on Thursday, June 13. The future king was without his future queen Kate, Princess of Wales, and the “secret meeting” has become shrouded in mystery. There was no advance announcement of the conclave, and His Royal Highness’ trip appeared in the Court Circular — which has historically published the public activities of the senior royals the next day — as a listing on Friday, June 14. The one-sentence summary read: “The Prince o…