Which 1982 law severed Canada's remaining legal dependence on the UK Parliament?

The 1982 law that severed Canada’s remaining legal dependence on the UK Parliament was the Canada Act 1982.

Enacted by the Parliament of the United Kingdom, the Canada Act 1982 gave legal effect to Canada’s Constitution Act, 1982, including the Canadian Charter of Rights and Freedoms. Its most important constitutional consequence was ending Westminster’s authority to amend Canada’s Constitution.

Before 1982, Canada governed itself domestically but still relied on the British Parliament for constitutional amendments because no Canadian procedure existed for changing the British North America Act, 1867. This final transfer of constitutional authority is often called patriation.

A common mix-up is the Statute of Westminster, 1931. That statute granted Canada broad legislative autonomy, but it did not end the UK Parliament’s role in constitutional amendments. The Canada Act 1982 completed that process.