Statute of Westminster 1931: The British Parliament establishes legislative equality between the UK and the Dominions of the Commonwealth—Australia, Canada, Newfoundland, New Zealand, South Africa, and Ireland.

The Statute of Westminster 1931 is an act of the Parliament of the United Kingdom that significantly increased the autonomy of the Dominions of the British Commonwealth.

The Parliament of the United Kingdom of Great Britain and Northern Ireland is the supreme legislative body of the United Kingdom, and may also legislate for the Crown Dependencies and the British Overseas Territories. It meets at the Palace of Westminster in London. Parliament possesses legislative supremacy and thereby holds ultimate power over all other political bodies in the United Kingdom and the Overseas Territories. While Parliament is bicameral, it has three parts: the sovereign, the House of Lords, and the House of Commons. The three parts acting together to legislate may be described as the King-in-Parliament. The Crown normally acts on the advice of the prime minister, and the powers of the House of Lords are limited to only delaying legislation.

A dominion was any of several largely self-governing countries of the British Empire, once known collectively as the British Commonwealth of Nations. Progressing from colonies, their degrees of colonial self-governance increased unevenly over the late 19th century through the 1930s. Vestiges of empire lasted in some dominions well into the late 20th century. With the evolution of the British Empire following the 1945 conclusion of the Second World War into the modern Commonwealth of Nations, finalised in 1949, the dominions became independent states, either as Commonwealth republics or Commonwealth realms.

The Commonwealth of Nations, often referred to as the British Commonwealth or simply the Commonwealth, is an international association of 56 member states, the vast majority of which are former territories of the British Empire from which it developed. They are connected through their use of the English language and cultural and historical ties. The chief institutions of the association are the Commonwealth Secretariat, which focuses on intergovernmental relations, and the Commonwealth Foundation, which focuses on non-governmental relations between member nations. Numerous organisations are associated with and operate within the Commonwealth.