Today sees the publication of a new book by the Unit’s Meg Russell and Lisa James, The Parliamentary Battle over Brexit. Here the authors summarise some of its key findings about why parliament was drawn into such controversy over the implementation of Brexit. They reflect on what these events teach us about our constitution, as well as what may need to change in order to avoid repeating such problems, and to mend the damage done.

The UK’s arguments over what became known as Brexit began long before the June 2016 referendum, and continued with increasing bitterness afterwards. Parliament was often central, both as a venue for such arguments, and in terms of disputes about its proper role. It and its members frequently faced criticism and blame. Our new book, published today, charts The Parliamentary Battle over Brexit, from the early pressures for a referendum, through disputes about the triggering of Article 50 and control of the House of Commons agenda, the repeated defeats of Theresa May’s deal, and Boris Johnson’s unlawful parliamentary prorogation, to the UK’s eventual departure from the EU following his deal. The book charts what happened, but also asks what went wrong and whether things could have been handled differently. It reflects on what these events teach us about the functioning of our constitution, and what if anything might need to change.

The book includes a wealth of detail about key political moments, and the roles of different individuals and groups. Here we focus on some of the bigger questions about the lasting legacy of the battles over Brexit for the culture and institutions of UK politics, and particularly for the place of parliament itself. A fuller version of this analysis appears in the final chapter of the book.

Referendums and public participation

The referendum of 23 June 2016 was only the third ever such UK-wide vote (the first being on European Community membership in 1975, and the second in 2011 on changing the House of Commons voting system). The handling of the referendum was the single biggest error of the Brexit process, from which many other difficulties flowed.

Unlike the 2011 referendum, which was underpinned by legislation setting out the detail of the proposed new voting system, no clear prospectus was offered to the voters for Brexit. Prime Minister David Cameron hoped to use the vote – described disapprovingly by the House of Commons Public Administration and Constitutional Affairs Committee as a ‘bluff call’ referendum – to make the question of Brexit go away. Parliament never debated the substance of the question, the government did not detail the options, and civil servants were forbidden from preparing for a Leave vote. Leave campaigners argued at the level of principle, rather than on a specific plan. As one Brexit-supporting interviewee told us, ‘it was only [after the referendum] that different types of Brexit started coming to the fore. Soft Brexit and hard Brexit had never been canvassed before the referendum; the expressions were coined afterwards’. Issues that would soon come to dominate the agenda, such as membership of the Customs Union or Single Market, and crucially the Northern Ireland border, were barely mentioned during the campaign. This left the government – and parliament – in a very difficult position. The different options for Brexit had to be established only after the vote had taken place, and on this the voters had conveyed no clear instruction.

In this light, it was remarkable that consultation with the public effectively ceased after the referendum. The result was close, and the country divided. But rather than admitting the complexities, and encouraging public deliberation on the options, the new Prime Minister Theresa May adopted a distinctly closed style, in terms both of parliament and the wider public. The Constitution Unit’s Citizens’ Assembly on Brexit found support in 2017 for a compromise around a soft Brexit, but this was an unofficial exercise, and no such routes were ever pursued by the government.

The sovereignty of parliament

A key argument by Leave campaigners was the need to regain ‘parliamentary sovereignty’ – presented as central to ‘taking back control’. Such claims often in practice elided concerns about national sovereignty with the language of parliament, and significant confusion emerged later over where domestic sovereignty should lie.

Arguments soon emerged about the extent of parliament’s say over the Brexit process, and the institution was quickly denounced for getting in the way. The sovereignty of parliament was core to the two legal cases which ended up in the Supreme Court. The first, in 2017, concluded that legislation was needed to authorise the triggering of Article 50, rather than the government being able to do this using prerogative powers. This question became a battleground, with Theresa May accusing those pursuing the case of ‘trying to subvert’ democracy. The government claimed a mandate on the basis of the referendum – ostensibly pitting direct democracy against the UK’s traditional representative democracy. But very often these arguments were really ones about executive versus parliamentary power.

This was clearly true in the second Supreme Court case over Boris Johnson’s attempted lengthy prorogation of parliament in autumn 2019. Johnson also claimed a mandate from the referendum – despite the lack of a prospectus, and he himself having been among those who voted to block Theresa May’s Brexit deal. Meanwhile some of his opponents claimed that parliament’s assertiveness was ‘what the Parliamentary sovereignty so desired by many Leavers looks like’. Throughout the Brexit debates, the ‘sovereignty of parliament’ was claimed by different protagonists to support competing ends.

Political parties and parliament

Theresa May’s repeated failures to find a parliamentary majority for her Brexit deal in 2019 placed enormous pressure on the House of Commons. With the Article 50 clock ticking, cross-party groups of MPs who feared ‘crashing out’ without a deal began exploring whether some other kind of majority could be found. This resulted in headlines about MPs ‘seizing the agenda’, and growing acrimony over the House of Commons rules. Ultimately ‘indicative votes’ on alternative Brexit outcomes failed to reach agreement, leading Brexit-supporting newspapers to complain that ‘[w]e voted for Brexit, all you say is no’.

But the inability of cross-party backbench groups to succeed where the government had failed was unsurprising. The Brexit battles starkly illustrated just how much the normal functioning of parliament relies on relatively cohesive political parties. The governing party was deeply split, with 118 Conservative MPs voting against Theresa May’s deal on the first occasion, and 34 resisting even the third time round. The government itself was internally split – described to us by one Cabinet interviewee as divided into ‘armed camps’ over Brexit. The primary failure was therefore one of government, not parliament.

Brexit also highlighted other key problems in the political parties, particularly in terms of their systems for choosing leaders. Labour’s Jeremy Corbyn had been elected leader without the support of his MPs, and party members re-elected him in 2016 despite a crushing no confidence vote in his own parliamentary party. Corbyn’s presence narrowed the options for Theresa May to outflank her hardliners by cutting a cross-party deal. Subsequently it prevented rebel Conservative moderates from building a stable cross-party alliance against Boris Johnson. As further illustrated later by Liz Truss, member ballots fundamentally undermine accountability in systems of parliamentary democracy.

Government and parliament

Much of the Brexit story concerns the central tensions between government and parliament. May’s government sought to proceed as far as possible without parliamentary consultation and approval, which led to backlash. Johnson’s government then sought to shut parliament down.

These tensions were fuelled by the highly unusual circumstances of minority government after the 2017 general election, for which both government and parliament were ill-prepared. The standard option in the circumstances of minority government of dropping the most controversial policies was not available in the case of Brexit. The prospect of delivering on a divisive referendum which lacked any prospectus, with a divided party, in these circumstances would have tested any leader. Meanwhile, Theresa May was temperamentally unsuited to the situation, and Boris Johnson even more so.  But parliament’s own rules also did not help. Minority government made ministers’ traditional control of the House of Commons agenda particularly problematic. This led to the ‘seizing’ of the agenda, rather than a more rational sharing of time. The Wright Committee of 2009-10 had proposed change in this area. Brexit showed that in this and other respects, it would make sense for the House of Commons to indeed ‘take back control’.

An unfortunate effect of this period was how government became increasingly resistant to parliamentary scrutiny. Such instincts were understandable given the controversy over Brexit, and the minority situation. Next followed COVID-19, and the exceptional need to legislate at speed. But the legacy of this resistance to scrutiny remains with us still. The Retained EU Law (Revocation and Reform) Bill, and timetabling of the Illegal Immigration Bill, make clear that some very bad habits have become ingrained. An urgent priority is to rebuild a culture of scrutiny, which is essential to the democratic legitimacy of government, and to making policy well.

Populism and the wider culture of politics

A particularly damaging legacy of this period is more cultural than institutional. Populist politics, which pits allegedly ‘out-of-touch elites’ against a pure ‘people’, did not begin in the UK with the Brexit referendum, but was greatly fuelled by it and subsequent events. Media headlines about judges being ‘enemies of the people’, and Theresa May’s claims to the public to be ‘on your side’ against a recalcitrant parliament, fuelled polarisation and resentment against the UK’s core democratic institutions. Such populist rhetoric helped facilitate Johnson’s prorogation, followed by a Conservative manifesto that claimed MPs had ‘devoted themselves to thwarting the democratic decision of the British people’ (notwithstanding his own earlier complaint that May had been ‘wrong in every sense to blame MPs for blocking Brexit’).

Populism poisons the well of democratic debate, conjuring up heroes and villains and suggesting that there are easy answers, rather than acknowledging the compromise and negotiation that is essential to politics in a complex world. By fuelling resentment and polarisation it risks turning people against both each other, and the institutions upon which democracy depends. The UK’s seemingly stable democracy proved itself to be far from immune to these forces during the Brexit debates.

Thankfully, public opinion has subsequently shown itself to be strongly supportive of high standards in politics, and the maintenance of constitutional checks and balances. But the battle over Brexit demonstrated that there is no room for complacency about the state of our democracy, and we must respect and value our institutions.

The Parliamentary Battle over Brexit is published today by Oxford University Press. Click the link for further details about the book, and to purchase it with a 30% discount on the £25 retail price. The Unit is also running two free events to promote the book, entitled The Parliamentary Battle Over Brexit and the Constitution, and The Parliamentary Battle over Brexit and the Conservative Party. Tickets are available via the Unit’s events page.

About the authors

Meg Russell FBA is co-author of The Parliamentary Battle over Brexit, Professor of British and Comparative Politics at UCL and Director of the Constitution Unit.

Lisa James is co-author of The Parliamentary Battle over Brexit and a Research Fellow in the Constitution Unit.