The Sewel Convention sits at the centre of the UK’s territorial constitution. It is often presented as a simple principle: Westminster will not normally legislate on devolved matters without the consent of devolved legislatures. Named for Lord Sewel in early debates on the Scotland Act 1998, it was intended to manage the relationship between the absolute legal sovereignty of the UK Parliament and the practical political autonomy of the new administrations in Edinburgh, Cardiff and Belfast.
That description, however, has always been optimistic. In practice, the convention depends on political restraint by the UK government. Recent developments have exposed the limits of this arrangement. Labour’s 2024 promise to ‘reset’ relations raised expectations of change, but little has followed. With devolved elections approaching in May 2026, and nationalist parties likely to perform strongly, the future of the convention looks increasingly uncertain.
The Sewel Convention
Two features are central, then, to the operation of the Sewel Convention. First that it is strictly political, not legal. This was definitively confirmed by the UK Supreme Court in the Miller case in 2017. There, the Court held that while the convention is a fundamental part of the constitutional landscape, it does not create legally enforceable duties. Even after the convention was formally recognised in the Scotland Act 2016 and the Government of Wales Act 2006, the judiciary maintained that its inclusion in law was merely a description of a political practice. It did not make the convention ‘justiciable.’ This means that if the UK government decides to ignore a lack of consent, the courts have no power to intervene or strike down the resulting legislation on the basis of the convention.
Second, Sewel is qualified by the phrase ‘not normally.’ This wording originates in Lord Sewel’s statement during the passage of the Scotland Act 1998 and was later reflected in statutory form in the Scotland Act 2016 and the Wales Act 2017. This creates a significant amount of room for interpretation. What counts as a ‘normal’ situation is not defined in any law or official handbook. Historically, this lack of a definition was seen as a strength, as it allowed for flexibility during national emergencies. However, because there is no independent body to decide what constitutes an exception, the definition ultimately depends on the UK government’s own judgment.
These two features combine to give the UK government considerable control over the operation of the convention. It is able both to determine when the convention applies and to decide what follows when consent is withheld.
The convention itself operates through legislative consent motions. Where Westminster legislation touches on devolved matters or alters devolved competence, consent is sought from the relevant legislature. In the early years of devolution, this process functioned with little friction. Consent was routinely granted. This reflected a context of political alignment and relatively low levels of constitutional conflict. That context has changed since, though, and a convention which was designed for cooperation now more often operates amid conditions of sustained disagreement.
The definition of ‘normal’ and the Brexit shift
Perhaps the most significant challenge to the Sewel Convention came during the Brexit process. For the first time since 1997, the UK government began to routinely override the refusal of consent of the Scottish and Welsh legislatures. When the Scottish Parliament and Welsh Senedd withheld consent for the European Union (Withdrawal) Act 2018, the UK government issued a formal statement justifying its decision to proceed. It argued that the ‘unprecedented’ nature of Brexit meant that the circumstances were ‘not normal.’
By using this justification, the government effectively turned the ‘not normally’ clause into a tool for bypassing devolved objections. This shift changed the nature of the convention. Instead of being a barrier that forced the UK government to negotiate and find common ground, it became a rule that could be set aside whenever a major constitutional change was deemed sufficiently important by Westminster. This has led to a sense of ‘consent fatigue’ in the devolved legislatures, where the act of refusing consent feels increasingly like a symbolic gesture rather than a practical exercise of power.
The UK Internal Market Act 2020 further complicated this dynamic. It introduced rules to ensure smooth trade across the UK, but in doing so, it restricted the ability of devolved governments to set their own standards in areas like environmental protection or food safety. Even when the Sewel Convention was technically followed, the practical authority of the devolved institutions was reduced. This reinforced a growing belief that the convention provided only a thin layer of protection that can be managed or bypassed when it conflicts with a UK government’s broader economic or political goals.
Current Problems and the Absence of a ‘Reset’
Labour’s 2024 commitment to a reset of intergovernmental relations appeared to acknowledge this decline in trust. The preceding Brown Commission had suggested that the Sewel Convention needed to be reinforced to prevent it from being ignored. The Party’s language more generally of partnership and respect suggested a return to the cooperative practices of the early 2000s.
Yet, there has been very little concrete movement toward reform. Labour’s 2024 manifesto notably included a commitment to strengthen the Sewel Convention through a renewed Memorandum of Understanding setting out how the UK government and the devolved administrations would work together for the common good. On one reading, this suggests an attempt to give greater structure to the operation of the Sewel Convention, potentially by clarifying expectations around consultation, cooperation, and the circumstances in which consent may be withheld or overridden. However, there is little indication that this commitment has translated into meaningful changes in practice. No new rules have been introduced to the House of Commons to ensure that devolved concerns are given more weight, nor is there any clearer framework governing when Westminster should proceed without consent. The convention remains formally intact, but it has been weakened by years of being overridden. Recent reports, such as those from the United Kingdom Constitution Monitoring Group (UKCMG), note that there has been limited progress in restoring the practical force of the convention. The gap between the promise of a ‘reset’ and the reality of institutional change is now difficult to ignore.
The result is a convention that continues to exist as a part of the UK’s constitutional theory, but no longer shapes the outcome of legislation in the way it once did. It currently operates as a signal of disagreement rather than a requirement to form consensus. The UK government has learned that it can navigate the political fallout of proceeding without consent, which reduces the incentive to seek agreement in the first place.
Looking ahead: Sewel after the 2026 elections
The next phase of this story will be shaped by the May 2026 devolved elections. If nationalist parties form the governments in Scotland and in Wales (for the first ever time) the conditions for achieving consent will become more difficult. We may see a period where the refusal of legislative consent becomes a regular occurrence rather than a rare exception.
In that scenario, the UK government will face a clear choice. It can treat the Sewel Convention as a meaningful constraint and change its policies to secure agreement, or it can continue to legislate without consent and accept the damage this does to the territorial settlement. If the latter path is chosen, the convention risks becoming purely symbolic. It will mark the points of disagreement between the different nations of the UK, but it will not prevent central government from acting.
There is also a deeper question about democratic legitimacy. Devolved elections provide a mandate for governments to act on behalf of their voters. When those mandates lead to a refusal of consent, and that refusal is ignored by Westminster, the link between devolved democracy and the law-making process becomes weaker. While the Council of the Nations and Regions may help manage some of these disputes, institutional tweaks alone are unlikely to restore the convention to its original position. The Sewel Convention was always based on political practice rather than legal certainty. As that practice continues to shift, the question for the future is not whether the convention still exists, but whether it is still capable of reinforcing the Union.
Darryn Nyatanga.
Dr Darryn Nyatanga is a constitutional law scholar whose research focuses on executive power, devolution, and constitutional change in the United Kingdom. He holds a PhD from the University of Liverpool.
The Constitution Society is committed to the promotion of informed debate and is politically impartial. Any views expressed in this article are the personal views of the author and not those of The Constitution Society.