Constitutional Conventions and Prerogative Power

Introduction

Unlike most states, the United Kingdom has **no single, codified constitutional document**. Its constitution is drawn from a variety of sources and is held together as much by **practice and convention** as by law. This chapter introduces the **nature and classification of constitutions**, the **core constitutional principles** on which the UK constitution rests (the **rule of law**, the **separation of powers** and **parliamentary supremacy**), and the **four principal sources** of the UK constitution. It then examines two of those sources in detail: the **royal prerogative** and **constitutional conventions**, and the way in which they interact with legislation.

Assessment focus

For the SQE1 FLK1 assessment, you must understand the **nature of the UK constitution** and be able to classify it as **unwritten, monarchical, unitary, flexible** and having an **informal separation of powers**. You should be able to identify the **core constitutional principles** (rule of law, separation of powers, parliamentary supremacy) and the **four principal sources** of the constitution (Acts of Parliament, case law, the royal prerogative and constitutional conventions). You must be able to explain the **definition and function of constitutional conventions** — that they are binding in practice but **not legally enforceable** — and the **scope of royal prerogative powers**. Questions are single best answer questions (SBAQs) set in realistic scenarios; you will be expected to **classify** the constitution and **identify sources and principles** rather than merely recall definitions. This is a closed-book assessment — recall the core concepts, distinctions and examples from memory.

Study tips

1) Memorise the **five classifications** of the UK constitution: **unwritten, monarchical, unitary, flexible, informal separation of powers**. 2) Memorise the **three core constitutional principles**: **rule of law, separation of powers, parliamentary supremacy** — and link parliamentary supremacy to **A.V. Dicey**. 3) Memorise the **four principal sources**: **Acts of Parliament, case law, royal prerogative, constitutional conventions** (a frequent SBAQ point). 4) Learn the two classic definitions of conventions: **Marshall and Moodie** ('rules of constitutional behaviour... not enforced by the law courts') and **Jennings** ('the flesh which clothes the dry bones of the law'). 5) Remember key **prerogative powers** — the power to **declare war** and to **make international treaties** — exercised by ministers on behalf of the monarch.