Constitutional status
In the United Kingdom, Elizabeth II's succession to the throne is based on the Act of Succession to the Throne of 1701, and she is a Protestant Christian and is also unmarried to a Roman Catholic. Although the British throne is generally inherited by blood, the Parliament of the United Kingdom has had the power to decide who succeeds to the throne since the Glorious Revolution of 1688. (See Succession to the British throne)
Of the 15 Commonwealth countries that recognize Elizabeth II as head of state, her status as head of state is constitutionally recognized. Originally, all of these countries had been British colonies or self-governing dominions. The earlier Statute of Westminster, which was used to distinguish between British colonies and self-governing dominions of the British Empire, according to which "any law which may alter the succession to the throne and the titles of the Crown shall only be carried into effect with the assent of the Parliament of the United Kingdom and the Parliaments of all the self-governing dominions." And the 15 countries that continued to recognize the Queen (or King) as their head of state after independence in fact achieved something close to this status of self-governing dominions, even though they were not self-governing dominions under the Westminster Act and did not have the right to decide on their own to change the method of succession. When Elizabeth II died her descendants would become their heads of state in accordance with the constitutions of those countries, not in accordance with the principle of succession. So in fact Canadians, Australians, etc. cannot be called "the Queen's people".
16 countries where Elizabeth II is head of state:
Antigua and Barbuda
Australia
Bahamas
Barbados
Belize
Canada
Grenada
Jamaica
New Zealand (since 1981. The British monarch, who is head of state of New Zealand, is also head of state of the Cook Islands)
Papua New Guinea
St. Kitts and Nevis
St. Lucia
St. Vincent and the Grenadines
Solomon Islands
Tuvalu
United Kingdom