Clerk of the Privy Council John Hannaford participates in a signing, as Gov. Gen. Mary Simon and Prime Minister Justin Trudeau look on. Hannaford is seated while the PM and GG stand behind him looking over his shoulder.

Canada's senior public servant has invited his provincial and territorial counterparts to apply for top secret-level security clearance as a way of fostering "healthy, transparent dialogue" on foreign interference and other threats.