[2] This act combined the Province of Canada (now Ontario and Quebec) with Nova Scotia and New Brunswick into a Dominion within the British Empire.

Manitoba, Newfoundland and Quebec responded by posing references to the provincial courts of appeal, challenging the federal government's power to seek unilateral amendments from Britain.

[11] Trudeau succeeded in convincing nine provinces out of ten to consent to patriation by agreeing to the addition of a Notwithstanding Clause to limit the application of the Canadian Charter of Rights and Freedoms[12] as a result of discussions during a First Ministers' conference and other minor changes in November 1981.

Citing concerns over Canada's past mistreatment of Quebec and Indigenous peoples (as recalled with frustration by Jean Chrétien in his memoirs Straight from the Heart),[15] 24 Conservative and 16 Labour MPs voted against the act.

However, new research into documents of the Margaret Thatcher government indicate that Britain had serious concerns about the inclusion of the Canadian Charter of Rights and Freedoms within the Canada Act.

Part of this concern stemmed from letters of protest the British received about it from provincial actors, but also because the Charter undermined the principle of parliamentary supremacy, which until that time had always been a core feature of every government practising the Westminster system.

The Canada Act 1982 received royal assent on March 29 in London, but it did not take full effect immediately.