“[W]e should move to a system of proportional representation for the election of the Commons. … Every person and every place will only be equal when every vote is equal. Under the present system, some people and places are more equal than others.” Andy Burnham in “Head North”, p.194
“[I have spoken] before about leaving this place 10 years ago, standing for the first time under a proportional system and seeing how it changed the conversation on the doorstep, where all of a sudden there was an incentive to look for a point of agreement, rather than to score points, as I have been saying. That experience changed me. Where I disagree with her is in saying that we should do that ahead of any general election, because I believe there needs to be a mandate to make that change. There are different views in this House, but I believe that we will need to get a consensus at the next election, and if there is that consensus, a change can be made in the next Parliament.” The Prime Minister, Hansard, 1 September 2026, col.40, in answer to a question from Lisa Smart MP.
As both those quotes show, supporters of electoral reform now have a champion in Number 10. As the second quote shows, they also have a champion who has a sense of direction about how to achieve it: to build consensus and then to obtain a mandate for that change at the next election.
That broad strategy raises two questions. First, is it constitutional to bring in electoral reform in that way? Second, what is the route map to achieving consensus?
Is it constitutional?
The question as to whether a reform of this kind is constitutional needs to be answered at two levels.
The first level is what might be called the level of pure law: in short, whether any challenge in the courts to such a change could succeed. That question can be answered shortly: if the change is achieved by an Act of Parliament, then that Act would be recognised by the courts and any challenge to it would fail. So the question of constitutionality, at that level, collapses into the question of whether Parliament would pass such an Act. Some supporters of electoral reform have argued that that could be done before the next election, given that there is (probably) now a majority of support in principle in the House of Commons. However, the Prime Minister’s reference to there needing to be a mandate for such a change is, in part, a reference to the unreality of that suggestion. There remains substantial opposition to electoral reform among Labour MPs, who could (rightly) point to the absence of any proposal for electoral reform in the manifesto on which they stood; and it is possible that the House of Lords, which could delay the legislation for a year or more, would use its delaying power on the ground that such an important change needed a mandate (the “Salisbury convention”, by which the Lords never uses that power for legislation promised in the winning party’ manifesto, would obviously not apply). Since legislation would have to be in place well before an election in order, for example, to enable the drawing of new electoral boundaries, those factors rule out reform before the next election.
The second level is the level of legitimacy: whether the public at large, and in particular those who opposed the change, would accept the change as legitimate. It is, I think, at that level that the Prime Minister was primarily operating when said that there “needs to be a mandate to make that change”.
Questions of legitimacy are bound up with questions of constitutional convention: established understandings as to how political actors should and should not behave. In relation to electoral reform, the key question is whether there is any kind of constitutional convention that such a change would require a referendum, even in circumstances where majority of the Commons had been elected on a manifesto proposing such a change. Those that say that there is such a convention point to the 2011 referendum, during the Conservative/Liberal Democrat coalition government, on the introduction of the Australian system (preference voting in single-member constituencies – not a proportional system).
However, that referendum was on a proposal that figured in neither governing party’s previous election manifesto (the Conservatives opposed any electoral reform; the Lib Dems proposed a proportional system). The only reason it was held is that the governing parties agreed to hold it as part of the compromise between themselves reached in order to form a coalition government. It therefore provides no support for the view that a referendum is required where such a proposal is included on a winning manifesto.
Further, over the two centuries during which Parliament has made profound changes to the United Kingdom’s electoral system, including successive widening of the franchise, abolishing double-member constituencies, introducing the secret ballot, or reforming the electoral systems for local elections (as has recently been done, by both the last and the current Parliament, in relation to the voting system used for mayoral elections), there is no occasion on which a referendum was judged to be a requirement for a legitimate change. Against that history, it is not credible to suggest that even a profound change to the voting system cannot legitimately be made without a referendum.
The answer to the question of whether it is constitutional to bring in a change to proportional representation in the way outlined by the Prime Minister is, therefore, a clear “yes”.
What is the route map?
The Prime Minister has identified the need for a “consensus”. At one level, that might look unrealistic. It seems clear that neither party of the right will support such a change given that neither of them has any realistic coalition partners or any realistic hope of winning anything like a majority of votes on their own, but a non-negligible chance, if the lottery of first-past-the-post cashes out in their favour, of winning a House of Commons majority on somewhere around 30% of the vote. Moreover, there are those with deep principled objections to electoral reform, including on the Labour benches, usually on the ground that first-past-the-post is said to generate stable one party majorities (although the number of people holding that view is slowly reducing as the prospect of the UK returning to the kind of two-party system on which the “FPTP produces stable majorities” argument depends becomes ever more remote).
However, two other objectives are rather more realistic, and may well be what the Prime Minister had in mind.
The first is to achieve a wider public understanding of what electoral reform is about and what the arguments for it are, particularly in a multi-party system, and particularly given the successful experience of (different) proportional systems in Scotland, Wales, and Northern Ireland/Ireland (indeed, the different systems could sensibly be labelled as the “Scottish” and “Irish” systems so as to remind everyone that these systems are already successfully used in these islands). Such a public understanding would help defuse bad arguments – usually based on systems, such as that of Israel, that no-one would suggest are appropriate for the UK – that are bound to be used by opponents of electoral reform during an election campaign.
The second is to achieve a consensus between supporters of electoral reform as to what proportional system should be adopted. The Prime Minister, in his book, indicated his support for the Scottish system (single-member constituency MPs plus a top up regional list to ensure proportionality): but many reformers see advantages in the Irish system of multi-member constituencies and preference voting.
How are those objectives – public understanding and a consensus as to the type of change – to be achieved before the election?
Campaigners for electoral reform have, in my view, rightly focused on the idea of a National Commission on Electoral Reform (NCER). But that idea raises a host of further questions to which thought needs to be given. Who should be members of the NCER? How can the NCER avoid being seen as composed of people who have already made up their minds (given that most people with the necessary background or expertise will already have public views on the topic)? How can the NCER engage with the public and attract their attention?
The answer to those questions may not matter if the main objective is to obtain consensus as to the choice of, and detailed design of, the proportional system. But if – as I think it is – the Prime Minister’s aim is the wider one of shaping public understanding of the issue, then public buy-in is essential. How can that be achieved?
An attractive answer to that question is to make a “citizens’ jury” a key part of the design of the NCER. A citizens’ jury would consist of ordinary citizens, probably around 100 or more, chosen at random from the electoral register, and paid to attend a number of sessions, read background material, and deliberate with each other on the questions raised. Citizens’ juries have been used in other countries: a well-known and close example is the use of a citizens’ jury in Ireland to formulate a new regime for legal abortion before the 2018 referendum on removing its constitutional prohibition of abortion. And there is now a well-developed literature on the design of effective citizens’ juries that can be drawn on.
The involvement of a citizens’ jury would itself attract attention as an innovative and democratic development. It would also confer legitimacy on the NCER and what it proposes: it would be difficult for opponents of reform to refuse to engage with the NCER, or plausibly to denounce its recommendations as a partisan stitch-up.
Of course, one risk of involving a citizens’ jury is that it might decide to keep the existing system. But that risk is inherent in any democratic answer to any question: and, at the end of the day, if the arguments in favour of electoral reform are not good enough to prevail before an informed group of ordinary citizens, then they won’t survive the scrutiny of a general election campaign.
A decision to put a citizens’ jury at the heart of the NCER would be bold, democratic, and principled, and so entirely in keeping with the Prime Minister’s approach to politics: it would be, in my view, the best route towards the Prime Minister’s objective of a solid mandate for reform.
George Peretz KC is Chair of the Society of Labour Lawyers and writes in a personal capacity.
