British Prime Minister Andy Burnham has called for the United Kingdom to adopt a written constitution, linking the proposal to his government’s plans to transfer greater power and financial control from Westminster to regional authorities.

Britain differs from most countries because it does not have a single codified document setting out the structure of the state, the powers of its institutions and the rights of its citizens.

Instead, the British constitutional system is spread across legislation, court judgments, international treaties and political conventions developed over centuries.

Burnham, who became prime minister on July 20, said his devolution programme could eventually pave the way for a new constitutional settlement.

He called for a clear set of principles governing how the country is run and how power is divided between Westminster, regional authorities and the devolved governments of Scotland, Wales and Northern Ireland.

Burnham argued that the absence of a written constitution forces regions to continually defend their powers and prevents local leaders from taking action without approval from the central government.

The former mayor of Greater Manchester has made decentralizing Britain one of the main priorities of his new government.

Under proposals announced by the government, regional mayors in England would retain a share of the income tax collected in their areas from 2028. They would also receive a greater portion of locally generated business rates from 2027.

The reforms are intended to give regional leaders more control over funding for housing, transport, employment, education, energy and public services.

Local authorities would also be allowed to borrow against future revenues to finance long-term infrastructure projects, reducing their dependence on short-term grants issued by the Treasury.

Burnham believes these devolved powers may eventually require constitutional protection to prevent future governments from withdrawing them without an agreed legal process.

Before entering Downing Street, he supported the introduction of a German-inspired “basic law” requiring the government to work toward comparable living standards across different parts of the country.

The proposal would represent a major change to Britain’s political system and could affect the long-established principle of parliamentary sovereignty.

It would also raise complex questions about the authority of Parliament, the courts, the government, the monarchy and the devolved legislatures.

Political experts have warned that writing and approving a constitution could take years and require extensive public consultation, parliamentary investigations and negotiations with regional governments.

There are also concerns that financial devolution could disproportionately benefit wealthier areas such as London and Greater Manchester unless it is accompanied by a system for redistributing revenue to poorer regions.

The government is considering mechanisms under which richer areas would contribute part of their revenues to regions with weaker economies and smaller tax bases.

Scotland, Wales and Northern Ireland have operated under devolved political systems since constitutional reforms introduced in the late 1990s.

England, however, remains one of the most centralized political and financial systems in Europe, despite the creation of several regional mayors and combined authorities during the past decade.

Former Labour Prime Minister Gordon Brown previously advocated constitutional reform, while a parliamentary committee examined several models during a five-year review completed in 2015.

The committee found no clear agreement on whether Britain needed a written constitution or what form such a document should take.

Burnham’s proposal does not mean that his government will immediately begin drafting a constitution. It does, however, bring the issue back into mainstream British politics and connect it directly to his attempt to redistribute power and resources away from Westminster.