Does the UK have a written constitution?
The nutshell
The UK has no single written document called 'the constitution'. Instead, its rules are spread across many laws, court rulings and customs built up over time.
Every fact on this page comes from Parliament's own guides and non-partisan experts. Each source tag — like Parl — opens where a fact comes from.
The basics
One country, no single rulebook
Most countries keep their main rules in one special document. That document is called a constitution. It sets out how the country is run, and what those in charge can and cannot do. The UK is different. It has no single document called 'the constitution'.Parl The rules are spread across many places instead.
Where the rules actually live
The UK constitution comes from several sources at once. Some rules are written in laws passed by Parliament, called statute law. Some come from decisions made by judges in court, called common law. Others are customs, known as conventions. A convention is a settled habit that people follow even though no law makes it a rule.HoC Together, these make up what is called the British Constitution.
Unwritten, or just uncodified?
People often call the UK constitution 'unwritten'. That is not quite right. Much of it is written down, just not all in one place.IfG A better word is uncodified. Codified means gathered into one single code, or document. Uncodified means the rules are real, and often written, but scattered across many sources.
Is the UK unusual?
Most democracies do have a single written constitution. The UK is one of only a few that do not, along with Israel and New Zealand, according to the Constitution Unit at University College London.CU Some people want the UK to write its constitution down in one document. Others want to keep the current system as it is.
- A single written document would gather the country's main rules into one place anyone could read
- Firm, protected rules would be harder for any one government to change on its own
- A written text could set out people's rights plainly, making them easier to defend
- Much of the constitution is already written down, just spread across many laws and court rulings
- The current system can adapt quickly to new needs, without a slow formal process
- A fixed written text could give judges the final say over the rules instead of elected MPs
The deep end6 min
What the constitution is made of
The UK constitution is often described as partly written and wholly uncodified. The House of Commons Library sets out four main sources: statute law passed by Parliament, common law built from court judgments, constitutional conventions, and works of authority, which are respected books that describe how the system works.HoC No single one of these sits above the others in one master document.
UK Parliament makes the same point in plainer terms. A constitution has never been set down as one code in the UK. Instead, the statutes, conventions, judicial decisions and treaties that govern how the country is run are grouped together and called the British Constitution.Parl
Written, unwritten, codified, uncodified
The word 'unwritten' is common but misleading. The Institute for Government notes that much of the constitution is written down, and that quite a lot of it is codified in law. The difference is that these written rules are not collected into a single constitutional document.IfG For that reason, 'uncodified' is the more accurate term.
This makes the UK unusual. The Constitution Unit at University College London records that the UK is one of only a few democracies without a written constitution in a single document, alongside Israel and New Zealand.CU
The debate about writing it down
Whether the UK should adopt a single written constitution is a live question, and views differ. Supporters of a written constitution argue that one clear document would make the rules easier to find, and harder for any single government to change alone. Defenders of the current system, including the Institute for Government, argue that an uncodified constitution can adapt quickly as needs change, and that much of it is already written down in law.IfG
The plain facts here are settled. UK Parliament, the House of Commons Library and the Constitution Unit all describe the constitution the same way. What stays open is not whether the UK has a single codified constitution, which it does not, but whether it should have one.