A very small group of countries has no single codified constitution: the United Kingdom, New Zealand, Israel, San Marino and Saudi Arabia, with Canada a partial case. All of them have constitutional law — rules about who holds power and how it changes hands. What they lack is one document you could print and bind. Everywhere else, and there are close to two hundred everywhere elses, has one.
Uncodified Is Not the Same as Unwritten
The phrase unwritten constitution is the one people use and it is misleading. Britain's constitution is written down in enormous quantity — it is simply written in many places rather than one.
The proper term is uncodified. A codified constitution is a single instrument, usually adopted at a founding moment, usually harder to amend than ordinary law, and usually supreme over it. An uncodified constitution is assembled from statutes, court decisions, conventions and authoritative texts, none of which has that special status.
The practical difference is entrenchment. In a codified system, a government that wants to change the constitution must clear a higher bar — a supermajority, a referendum, ratification by states. In an uncodified system, constitutional rules can in principle be changed by an ordinary majority on an ordinary afternoon.
The United Kingdom
Britain's constitution is the canonical example, and it is a pile rather than a document. It includes statutes — Magna Carta of 1215 in its surviving clauses, the Bill of Rights 1689, the Acts of Union, the Parliament Acts of 1911 and 1949, the Human Rights Act 1998, the devolution settlements. It includes the common law developed by judges over centuries. And it includes conventions, which are binding in practice and unenforceable in court.
The conventions do much of the heavy lifting. That the monarch grants royal assent to any bill passed by Parliament, that the prime minister commands a Commons majority, that ministers resign over departmental failures — none of these is law, and all are constitutional.
The organising principle is parliamentary sovereignty: Parliament can make or unmake any law, and no Parliament can bind its successor. That is why Britain has no constitutional court that can strike down primary legislation, and why the Supreme Court's 2019 ruling on prorogation was such an event — it drew a limit on prerogative power without claiming a power to void an Act.
New Zealand
New Zealand inherited the Westminster approach and has kept it, with characteristic tidiness: it passed a Constitution Act in 1986 that consolidates some of the material without being a codified constitution in the usual sense.
Its constitutional sources include that Act, the Bill of Rights Act 1990, the Electoral Act, the Treaty of Waitangi of 1840 and the body of law and practice around it, and Westminster conventions. The Bill of Rights Act is explicitly not supreme law — courts can declare legislation inconsistent with it, and Parliament may proceed anyway.
New Zealand is also the only country in this group with a unicameral legislature and no federal structure or upper house, which means the constraints on a governing majority are unusually light. The shift to mixed-member proportional representation in 1996 was adopted partly for that reason.
Israel
Israel's position is the result of a deferral that became permanent. The 1948 declaration of independence provided for a constitution to be adopted by October 1948. The constituent assembly could not agree — principally over the relationship between religion and state — and in 1950 passed the Harari Resolution, which decided to build a constitution chapter by chapter through Basic Laws instead.
Fifteen Basic Laws have been enacted since, covering the Knesset, the judiciary, the presidency, human dignity and liberty, freedom of occupation, and in 2018 the nation-state law. Together they function as a partial constitution, and in the 1995 Mizrahi Bank decision the Supreme Court held that Basic Laws have superior status and that ordinary legislation inconsistent with them could be struck down.
That holding is the centre of a long-running constitutional conflict. Because Basic Laws can be passed or amended by an ordinary Knesset majority, critics argue the court has claimed a power of review over legislation that is not meaningfully entrenched; defenders argue that without it nothing constrains a majority at all. The judicial reform confrontation of 2023 was this argument reaching its sharpest point.
San Marino's Statutes of 1600
San Marino claims the oldest surviving constitutional documents in the world in continuous use. Its Statutes of 1600, the Leges Statutae Republicae Sancti Marini, are written in Latin and still form part of the constitutional order.
They are not a constitution in the modern sense — they are a set of statutes governing the institutions of a mediaeval commune — and they are supplemented by a 1974 Declaration of Citizens' Rights that functions as a bill of rights. The country is governed by two Captains Regent serving concurrently for six-month terms, an arrangement descended from the Roman consulship and unbroken since the fourteenth century.
San Marino therefore has ancient written constitutional law and no single codified constitution, which places it on this list for reasons entirely unlike Britain's.
Saudi Arabia
Saudi Arabia's Basic Law of Governance, issued by royal decree in 1992, states in its first article that the Quran and the Sunna of the Prophet are the constitution of the kingdom.
The Basic Law itself sets out the structure of the state, the succession within the House of Saud, and the rights and duties of citizens, but it explicitly positions itself as subordinate to scripture rather than as supreme law. There is no elected legislature — the Consultative Assembly is appointed — and no constitutional court.
Whether this counts as having no written constitution or having a religious one is a matter of classification. What is clear is that there is no single secular instrument that is supreme over the sovereign's decrees.
Canada: The Partial Case
Canada is usually excluded from this list and belongs on it with a qualification. Its constitution is partly codified — the Constitution Act 1867 and the Constitution Act 1982, which includes the Charter of Rights and Freedoms and a domestic amending formula — and partly not.
The Supreme Court has held that the constitution also includes unwritten principles: federalism, democracy, constitutionalism and the rule of law, and the protection of minorities. It relied on them in the 1998 Quebec secession reference, which is among the most consequential constitutional judgments anywhere on the question of how a part of a country may leave.
Canada also carries an unusual feature in the notwithstanding clause, section 33, which allows a legislature to declare that a law operates despite certain Charter rights for a renewable five-year period — a codified constitution with a built-in override.
Why So Few
Codified constitutions are overwhelmingly the product of rupture. A country writes one when it becomes independent, changes regime, loses a war or emerges from dictatorship — moments when the terms of the state have to be settled explicitly because the old settlement has failed.
The United States wrote one in 1787 after separating from Britain. France has had many, each following a collapse. Germany's Basic Law followed 1945. Spain's followed Franco. South Africa's followed apartheid. Over half of all national constitutions currently in force were adopted after 1990, mostly by post-communist and post-colonial states.
The countries on this list are, with the exception of Israel, precisely those that have not had such a rupture. Britain's constitutional order has evolved continuously since 1688 without a founding moment that demanded a document. New Zealand inherited that evolution. San Marino has simply never stopped.
The Countries That Keep Rewriting Theirs
The mirror image of this list is the set of countries that have codified constitutions and replace them constantly. The average national constitution survives under two decades before being replaced — a finding from comparative constitutional research that startles people who assume the American model is typical.
The Dominican Republic has had more than thirty constitutions since independence. Venezuela, Ecuador, Bolivia and Thailand have each had many. Thailand has adopted around twenty since 1932, most following a coup, and each new charter has been drafted by whoever had just taken power.
France is on its fifth republic. Haiti has had over twenty constitutions. By contrast, the United States constitution of 1787 is the oldest codified national constitution still in force, and San Marino's statutes of 1600 are older still without being codified in the modern sense.
That comparison undercuts the simple case for codification. A written constitution that is replaced every fifteen years provides less predictability than an uncodified one that has evolved continuously for three hundred.
Does It Matter
The case for codification is predictability: citizens can read their rights, courts can enforce them, and a government cannot alter the rules by winning an ordinary vote. The case against is flexibility: an uncodified constitution adapts without the paralysis that amendment procedures can produce — the United States has amended its constitution seventeen times since the Bill of Rights, and not at all since 1992.
Britain's experience through Brexit and the prorogation crisis sharpened the argument considerably, with serious constitutional lawyers on both sides. The counter-example usually raised is that codification does not guarantee much on its own: a great many countries with admirable written constitutions do not observe them, and the document's existence is not the thing that constrains power.
What all six of these countries demonstrate is that the constitution that matters is the one actually followed — whether it is bound in one volume or scattered across four centuries of statute. The institution several of these systems are built around is covered in countries with a monarch as head of state, and the monarchies of the world sets out the rest.
