Does the UK have a written constitution?

No. The UK does not have a single written constitution, unlike most democracies. Its constitution is uncodified. It is made up of Acts of Parliament, court rulings, conventions and historic documents such as Magna Carta and the Bill of Rights 1689. Parliament can change it by passing ordinary laws.

Key parts of the UK constitution are found in laws such as the Bill of Rights 1689 and the Acts of Union. Others include the Parliament Acts 1911 and 1949, the Human Rights Act 1998 and the devolution Acts. Court judgments also shape it, as do works by constitutional writers. Together these sources set out how power is shared and limited.

Many important rules are conventions, which are unwritten but widely followed. Examples include the monarch giving Royal Assent to bills and the Prime Minister sitting in the Commons. Conventions can change over time and are not enforced by courts. Another example is that ministers are accountable to Parliament, and that the Lords does not block manifesto bills. Breaking conventions can cause political crises even when no law is broken.

The central principle is parliamentary sovereignty, meaning Parliament can make or unmake any law. Supporters of the current system say it is flexible and has evolved peacefully over centuries. Critics say it relies too much on politicians behaving well and leaves rights poorly protected. Some argue for a codified constitution that courts could enforce. Proposals for a codified constitution have been debated for decades.