The Dangers of the UK’s Uncodified Constitution
By Francesca Davis, Intern at Unlock Democracy
In most modern democracies, a single document lays out what those in power can and cannot do. This document is called a constitution. However, in the UK, we don’t have one!
Instead, we have an uncodified constitution spread across many sources: statutes, conventions, and court rulings. Some may argue that our uncodified constitution benefits from being more flexible, but it is also vulnerable to abuse and manipulation.
The flowchart above reflects on the last few years, which saw Brexit and the COVID-19 pandemic, and highlights just how easily constitutional flexibility turns into fragility. The need for a codified constitution in the UK has never been more urgent.
Increasing Executive Power Has Weakened Parliamentary Oversight
The Prime Minister and Cabinet hold significant power. In recent years, they have increasingly exercised it with minimal parliamentary oversight. A good example is the repeal of the Fixed-Term Parliaments Act in 2022 which restored the Prime Minister’s unilateral authority to dissolve Parliament without Parliament’s approval.
Broad legislative frameworks lacking detailed provisions, known as “skeleton bills,” have allowed major policy decisions to be implemented by Ministers with limited parliamentary debate. The use of these bills has grown significantly since 2019, reducing Parliament’s ability to hold the executive to account. According to a paper from Cardiff University, the Nationality and Borders Act 2022 was passed as a skeleton bill. [1] It granted the Home Secretary sweeping powers to remove people to ‘safe’ third countries through secondary legislation and changes to immigration rules. Parliament has largely accepted the increase in skeleton bills, raising serious concerns about the damage that this does to our democracy.
More and more laws are being rushed through without proper scrutiny. The Institute for Government released a report earlier this year stating that “expectations of legislative scrutiny have plummeted” and warning of a decline in parliamentary scrutiny. [2] The Rwanda Act was pushed through Parliament in just weeks, despite clear opposition in both the House of Commons and the House of Lords. A codified constitution could curb executive power by requiring sufficient time for parliamentary debate on every bill.
The Legal System Lacks the Power to Defend Our Basic Rights
With a codified constitution, the judiciary has clear authority to strike down unconstitutional laws. However, in the UK, this is not the case. The UK Supreme Court cannot strike down Acts of Parliament, even if they may violate human rights, because parliament is sovereign.
The courts can make sure the government complies with existing human rights laws, but since 2020, the Supreme Court has increasingly sided with the government in human rights cases. This could be because of political pressure to limit so-called "judicial activism", and recent attempts to repeal the Human Rights Act.
Even when the courts are willing to act, the public often does not have access to justice. A judicial review case must usually be filed within three months and can cost over £30,000.
Without entrenched rights, legal accountability becomes a luxury. So, a codified constitution would ensure that basic rights for the people are not left to the shifting political will of governments and judges, but are instead enforceable for all.
A Democratic Deficit Undermines Government Legitimacy
Our constitutional system is based on the principle of parliamentary sovereignty, but Parliament itself suffers from a democratic deficit. The First Past the Post voting system creates unfair results in elections. In the most recent 2024 general election, the Labour Party won 63% of the seats in Parliament even though they only received 34% of the vote. The chart illustrates how this creates a weak link between the will of the people and the composition of Parliament.
This issue is compounded by the fact that the House of Lords is entirely unelected. It is filled through an appointment process dominated by the Prime Minister, which is often criticised for cronyism. To which, currently at least, are added around 90 hereditary peers.
When you pair our broken electoral system and the lack of legitimacy of the second chamber, with the absence of constitutional protections, governments can implement significant policy changes with the backing of only a minority of the electorate, and with weak scrutiny or challenge.
The Undermining of Devolution
One of the most vulnerable aspects of the UK’s constitution is the devolution settlement for Scotland, Wales, and Northern Ireland. The UK’s uncodified constitution does not provide adequate protection for these devolved powers, meaning Westminster can overreach into devolved matters or even undo the devolution settlement.
Post-Brexit legislation like the Internal Market Act 2020 allows the UK government to override devolved decisions in areas like food safety, environmental standards, and trade. Also, in January 2023, the UK government used Section 35 of the Scotland Act to block a Scottish Gender Recognition Reform Bill, highlighting key tensions between central government and Holyrood.
During the COVID-19 pandemic, devolved governments implemented many different measures compared to Westminster, creating conflict and some confusion. This highlighted the lack of constitutional clarity over who holds final authority in times of crisis, which undermines the autonomy of devolved parliaments and reinforces calls for separation, such as in 2023–2024 where pro-independence rallies across Scotland showed continued public support for independence. A codified constitution would protect the rights of devolved governments, ensuring that the separation and sharing of powers is upheld.
Increasing political influence over the Civil Service
The Civil Service is meant to be politically neutral, supporting any government in power while providing expert advice. However, events like the sudden dismissal of Mark Sedwill in 2020 indicate that politics is seeping into Civil Service appointments. The Institute for Government stated in a 2020 report that the way Sedwill’s exit was handled "showed how easy it is to undermine the impartiality of the civil service." [3] Sedwill was serving as Cabinet Secretary when he was dismissed during a period of political reshuffling, sparking concerns about ministers having too much influence over what should be a politically neutral body.
The UK’s lack of a codified constitution means civil service neutrality rests on convention rather than law, unlike countries like the US, where formal protections make it easier to challenge political interference. This highlights the need for clearer safeguards in the UK system.
It is Time for a Written Constitution
The UK’s constitutional system was once praised for its pragmatism. However, recent years have exposed its weaknesses, including unchecked executive power, weak legal protections for human rights, democratic deficits, and the vulnerable devolution settlement.
A codified constitution would not fix all of the UK’s problems, but it would provide enforceable rights and a clear framework for accountability. It would reduce the ability of those in power to bend the system for political gain, and it would help restore public trust.
The time for constitutional reform is now.
[1] https://journals.sagepub.com/doi/10.1177/14737795231206156?icid=int.sj-abstract.similar-articles.4
[2] https://www.instituteforgovernment.org.uk/comment/illegal-migration-bill-legislative-scrutiny