Multi-party politics defines British elections this week

THURSDAY’S (May 1) British elections will be the biggest ballot test since last July’s Labour landslide. Yet, it is not just the ruling party under pressure, but also the main opposition Conservatives, which could allow for the biggest breakthrough for Reform UK leader Nigel Farage since the 2016 Brexit referendum.

The shakeup is potentially so significant that one of the UK’s top pollsters, John Curtice, asserts “the conditions are there for the biggest challenge to the political conventions of British politics since the 1920s”. What Curtice points to is the growing threat to the two-way Labour-Conservative duopoly that had dominated UK politics for a century, from Reform UK on the political right, and also the Liberal Democrats, Greens, Scottish National Party (SNP) and the Welsh Nationalist Plaid Cymru on the centre and left.

To be sure, the exact results remain uncertain of Thursday’s English council ballots, multiple English mayoral elections, Welsh devolved assembly ballots, and also a parliamentary by-election in Runcorn. Yet, what is already clear is the unusual, simultaneous unpopularity of both Labour and the Conservatives.

While Labour is suffering from the unpopularity that many incumbents are facing across the world, much of the electorate has still not forgiven the Conservatives for their own troubles in UK government office between 2010 and 2024. Moreover, the last time that these English Council seats were up for grabs was in 2021, when then-prime minister Boris Johnson was at the height of his popularity.

One of the reasons why Curtice may be correct in his bold, historical prediction is that 2024 saw the final stage of back-to-back general election landslides, in opposite directions. That is, 2019 witnessed a big Conservative win whereas 2024 saw a huge Labour victory.

The last time this phenomenon happened was more than a century ago – 1900 saw a Conservative landslide, and 1906 a big Liberal win.

The huge victory for the Liberals in 1906 helped catalyse a political realignment that led to the modern UK electoral system dominated by the Conservatives and Labour. Indeed, the 1906 win was the last time that the Liberals won an absolute majority in the House of Commons, and also was the last general election in which neither Labour nor the Conservatives won the popular vote.

Almost 120 years on from 1906, there are signs again of deep-seated disequilibrium in the political system. For one, the collective share of the vote currently for the Conservatives and Labour is one of the lowest in living memory.

So there is a significant possibility of key political change underway, as Curtice highlights. However, rather than giving way to a new two-party system, it might instead be the entrenchment of a multi-party system akin to multiple continental European countries – heralding a more unpredictable, uncertain political landscape.

The decay of the traditional Labour-Conservative two party post-war system is not a new phenomenon. In the period from 1945 to 1970, Labour and Conservatives collectively averaged in excess of 90 per cent of the vote, and also the seats won, in the eight UK general elections held in this period.

Yet, from 1974 to 2005, the average share of the vote won by the Conservatives and Labour fell significantly in the subsequent nine UK general elections in this period. This has brought about a significant political change that is, by and large, still unfolding in 2025.

It is the centrist Liberals, not Reform UK, which has probably done more to date to break the hold of the two major parties in power. From 1974 to 2005, the average Liberal share of the vote in general elections (including the Liberal/SDP Alliance from 1983-87) was just below 20 per cent, although the party slumped in the polls after forming a coalition government with the Conservatives from 2010 to 2015.

While Liberals have long taken votes from both major parties, the overall political impact on Labour has probably been greatest. The success of the Liberal/SDP alliance was one factor that helped contribute to Labour’s long period in opposition from 1979 to 1997, when it endured four consecutive general election defeats before Tony Blair’s successes.

Beyond the Liberals, several other parties have come to prominence too, including the SNP which currently governs in the Edinburgh-devolved parliament; the Greens, Plaid Cymru and Reform UK too. Reform UK’s predecessor organisation, the United Kingdom Independence Party (UKIP) also led by Farage, won the European parliament vote in the United Kingdom in 2014, thus becoming the first party other than the Conservatives or Labour to win a UK national election in over 100 years since the Liberals.

Driven in part by UKIP’s appeal, which was disproportionately to Conservative rather than Labour voters, then-prime minister David Cameron promised that if he won a majority in the 2015 general election he would hold an “in or out” referendum on the United Kingdom staying part of the European Union. So UKIP had a profound influence on the UK, given that the 2016 heralded Brexit.

One reason the apparent decline of the two-party system may make for a more unpredictable outlook for UK politics is that it is harder for any one organisation to secure a majority government in UK general elections. This is despite the “first past the post” voting system, which tends to provide the leading party a significantly larger number of seats in the House of Commons than would be given by a more proportionate electoral system.

To be sure, coalitions and the sharing of power have long been a feature of UK local government and devolved parliaments and assemblies outside of Westminster. However, this same dynamic may now become a more regular feature at the heart of the UK government itself in London.

Until 2010, when the coalition government was formed between the Liberal Democrats and the Conservatives, Labour and the Conservatives had won overall majority governments at every election since 1945. The only exception was the brief political interregnum between the February and October 1974 elections.

In 2017 too, the Conservatives failed to win an overall majority. Then-prime minister Theresa May therefore had to reach a co-called “confidence and supply” agreement with the Democratic Unionist Party from Northern Ireland.

Taken together, the UK’s longstanding two-party system may therefore be giving way to a more unpredictable political landscape. This is likely to be shown on Thursday with Reform UK, Labour, Conservatives, Liberals, Green, and Plaid Cymru all winning seats, while the SNP is favourite to retain power in next year’s Scottish elections.

The writer is an associate at LSE IDEAS at the London School of Economics