Each Concentrate revision guide is packed with essential information, key cases, revision tips, exam Q&As, and more. Concentrates show you what to expect in a law exam, what examiners are looking for, and how to achieve extra marks. This chapter first describes the UK legislature. The legislature of the UK is the Queen in Parliament. Parliament is bicameral, meaning that, apart from the Queen, there are two legislative chambers called the House of Lords and the House of Commons. The House of Lords—composed of life peers, senior bishops, and some hereditary peers—is guardian of the constitution through the work of the House of Lords Constitution Committee and protects the constitution and initiates and revises legislation. The House of Commons—composed of constituency representatives organized on party lines under the whip system—is the principal legislative chamber and plays a significant role in scrutinizing the executive. The discussion then turns to the legislative process, covering electoral law, alternative voting systems, and the devolution of the legislative function including the Wales Act 2017.