The deputy prime minister of the United Kingdom is the second highest ranking minister of the Crown and a member of the British Cabinet. The title is not always in use and prime ministers have been known to appoint informal deputies without the title of deputy prime minister. The incumbent deputy prime minister is Oliver Dowden who also serves as Chancellor of the Duchy of Lancaster and Secretary of State in the Cabinet Office.

The Cabinet of the United Kingdom is the senior decision-making body of His Majesty's Government. A committee of the Privy Council, it is chaired by the Prime Minister and its members include Secretaries of State and other senior ministers. Members of the Cabinet are appointed by the Prime Minister and are by convention chosen from members of the two houses of the Parliament of the United Kingdom, the House of Commons and the House of Lords.