Letters Patent, 1947

These letters, replacing the previous letters patent issued in 1931, reconstituted the Office of the governor general of Canada under the terms of the Constitution Act, 1867, expanding the governor general's ability to exercise the royal prerogative, thereby allowing her or him to use most of the "powers and authorities" lawfully belonging to the sovereign[5] and to carry out an increased number of the sovereign's duties in "exceptional circumstances".

In this way, a different set of letters patent were issued by the Crown each time a new governor was appointed, a custom that was continued by the British following the surrender of New France to the United Kingdom in 1763.

[10] The experiences of the Kingdom of Iceland during the Second World War also gave Prime Minister Louis St Laurent an example of how the lack of a regency act or similar mechanism could, in certain circumstances, provoke a constitutional crisis.

With no method to allow for the incapacity of the sovereign, the Icelandic parliament was forced into passing an illegal constitutional amendment and appointing Sveinn Björnsson as regent.

As a result, the 1947 letters patent were issued by King George VI later that year, allowing the governor general to carry out nearly all of the sovereign's duties in case of the monarch's capture or incapacity and, thus, negating the need for His Majesty's Canadian government to go through the process of passing legislation equivalent to the Regency Act.

[15] Even many years after the implementation of the letters patent, a variety of matters continue to be submitted exclusively to the sovereign, such as the creation of honours, the appointment of governors general, and authorizing declarations of war.

[21] Conversely, the Letters Patent, 1947, would not be sufficient to effect such a dramatic change as a transfer of power from the King to the governor general, as any changes to the role of both of these positions are subject to the amending formula provided in section 41 of the Constitution Act, 1982,[22] which requires alterations to the office of the King and the governor general be done through a constitutional amendment approved by Parliament and all the provincial legislatures.