1. Constitutional Practice and Parliamentary Sovereignty
Legally, most UK referendums remain advisory: Parliament is not bound to implement a result and must still legislate to give it effect.
In practice, however, results since 1997 have generally been treated as politically decisive, most strikingly in the case of the 2016 EU referendum, where a majority of MPs had personally favoured remaining in the EU but nonetheless voted to trigger withdrawal following the result.
The frequency of referendums on major constitutional questions since 1997, covering devolution, the electoral system, Scottish independence and EU membership, has led some commentators to describe a new constitutional convention under which significant changes to the way the UK is governed are put to a public vote before Parliament legislates.
2. Devolution and the Territorial Constitution
The 1997 to 1998 referendums converted the UK from a highly centralised unitary state into one with substantial devolved government in Scotland, Wales, Northern Ireland and London.
The 2011 Welsh referendum extended this by giving the Assembly full law-making powers in devolved areas.
The rejection of an elected assembly for North East England in 2004 meant that devolution did not extend on the same model to the English regions, leaving an asymmetric settlement sometimes summarised as the West Lothian Question, addressed only partially and temporarily through the House of Commons’ English Votes for English Laws procedure between 2015 and 2021.
The Belfast Agreement referendum also embedded the principle of consent directly into the Northern Ireland Act 1998: any future change to Northern Ireland’s constitutional status must itself be agreed through a referendum.
3. The Union and Continuing Pressure for Further Referendums
Although the 2014 referendum produced a no vote, it established the idea that Scotland’s continued membership of the Union rests on renewed popular consent.
The 2016 Brexit result, in which Scotland voted to remain while the UK as a whole voted to leave, was used by the Scottish Government to argue that circumstances had changed materially enough to justify a further independence referendum.
Attempts to hold a second referendum without the UK government’s agreement were tested in the courts, and in November 2022 the UK Supreme Court ruled, in a case referred by the Lord Advocate, that the Scottish Parliament cannot legislate for an independence referendum without Westminster’s consent. The question of a further Scottish referendum has remained a live and recurring issue in UK politics since 2014.
4. Party Politics
Divisions over Europe within the Conservative Party predate 1997 but were a central feature of the period covered here.
The commitment to an EU referendum was made partly to manage internal party disagreement and to counter the electoral challenge posed by the UK Independence Party during the early 2010s.
Instead, the referendum and its aftermath deepened Conservative divisions, contributing to three changes of prime minister between 2016 and 2019 (David Cameron, Theresa May and Boris Johnson) and to prolonged parliamentary conflict over the terms of withdrawal during 2017 to 2019.
The Labour Party was similarly divided over how to respond to the result, and its position on a further referendum became a significant feature of the 2019 general election, which was fought substantially on the question of whether and how to implement the 2016 result.
The referendum question was also linked to the emergence and electoral performance of UKIP before 2016 and the Brexit Party in the 2019 European Parliament elections.
5. Regulation and Campaign Conduct
The Political Parties, Elections and Referendums Act 2000’s framework of spending limits, designated lead campaigns and Electoral Commission oversight has applied to every UK-wide referendum since 2000.
The conduct of the 2016 campaign nonetheless generated continuing scrutiny of the regulatory framework, including subsequent Electoral Commission findings against campaign groups on both sides in relation to spending returns, and wider debate about the adequacy of rules on referendum campaign finance and online campaigning.
6. Turnout and Public Engagement
Referendums on questions of national constitutional significance have at times produced markedly higher turnout than routine elections: 84.6% in the 2014 Scottish independence referendum and 72.2% in the 2016 EU referendum both exceeded turnout in the general elections held closest to them.
Other referendums, including the 2011 AV referendum (42.2%) and most local mayoral and council tax referendums, have recorded much lower turnout, suggesting that public engagement with the referendum device has varied considerably according to the perceived significance of the question being asked.
7. Referendums as a Recurring Constitutional Tool
Taken together, the referendums held since 1997 mark a clear shift in UK political practice.
Where referendums had been used only once at UK level before 1997, at least eight referendums of national or UK-wide significance were held between 1997 and 2016, alongside a growing number of local referendums on mayoral governance and council tax, placed on a statutory footing by the Localism Act 2011. The referendum, once an exceptional device, became a regular part of how major changes to the UK’s constitutional arrangements were decided.
8. Conclusion
Since 1997, referendums have moved from being a rare and exceptional device in UK politics to a recurring instrument used to authorise devolution, to settle questions about the electoral system, and to decide the country’s constitutional future within the Union and its relationship with the European Union.
Their cumulative effect has been to reshape the UK’s territorial constitution, to realign party politics around the issues they raised, and to leave open questions, particularly over Scotland’s constitutional future and the balance of devolved power across the UK, that continue to shape political debate.
