The development of a multi-party system

The way in which parties are grouped and structured in a political system is known as a party system, with a number of parties in contention for political power. There are a number of different models, and it is open to debate which of these best describes the UK system at any given time. It is also important to note that, since the advent of devolution in the late 1990s, different systems have been in play in the component parts of the UK.

Here are the most important models found in a liberal democracy.

· A one-party-dominant system A number of parties, but only one has a realistic prospect of holding power.

· A two-party system Two parties compete for power at elections; other parties have no real chance of breaking their monopoly.

· A two-and-a-half-party system Two large parties are the main players, but are challenged by the growth of a smaller third party.

· A multi-party system A number of parties contend to form a government; coalitions become the norm.

Which of these models most closely fits UK politics at present?

Westminster: survival of the two-party system

The classic era of the two-party system was the period 1945-74, when Labour and the Conservatives won, on average, a combined 91 per cent of the votes and almost 98 per cent of the seats at Westminster. This was clearly coming under strain from the mid-1970s, with a period of minority Labour government followed by two long periods of single party dominance: the Conservatives from 1979 to 1997 and Labour from 1997 to 2010. The Liberals made modest gains, especially after forming an alliance with the Social Democrats in 1981, then merging with them to form the Liberal Democrats in 1988. Between 1979 and 2010, the two main parties' combined average share of the vote fell to 73 per cent.

Nonetheless the two-party system survived, largely as a result of the distorting effect of the first-past-the-post voting system, which limits smaller parties' ability to win seats. The two largest parties shared an average of 91 per cent of the seats, and they continued to monopolise government without the participation of the UK's third party.

The period of coalition government (2010-15) could be described as a two-and-a-half-party system. The Liberal Democrats secured 23 per cent of the vote in 2010 and enough seats to play a part in government, though only as the partner of a larger party in a coalition. Almost 35 per cent of voters supported parties other than the Conservatives and Labour in this election.

However, this proved a short-lived development. The 2015 general election heralded a return to 'business as usual' at Westminster. The Liberal Democrats were devastated at the polls, losing all but eight of their seats. The most startling aspect of the 2015 contest was the landslide victory of the SNP in Scotland, where they took all but three of the 59 seats. However, the SNP is a regional party, which is not a contender for power at Westminster, even if it is able to influence the outcome of some votes in the House of Commons. Essentially Westminster remains dominated by the two largest parties. As long as the first-past-the-post system remains in place, this is unlikely to change.

The 2017 election saw a 'hung Parliament' with no one party having an overall majority. Did this mean a swing away from the two party system? Yes and no. Yes because the DUP suddenly became very significant by keeping the Conservative government in power but no because the Lib Dems failed to recover the losses of 2015 so there were still only two parties with a realistic chance of forming a government. The 2019 election resulted in a return to two party politics- the Conservatives gained clear overall majority and Labour remained the opposition- The Lib Dems again failed to regain their third party position.

The devolved bodies: a variety of multi-party systems

The use of the Additional Member System (AMS) for elections to the Scottish Parliament and Welsh Assembly has produced very different outcomes from the trends observed at Westminster. A partly proportional system, it tends to increase the representation of smaller parties. Although the SNP has been in power in Scotland for almost a decade now, it formed a minority government from 2007 to 2011 and once again after the May 2016 election. Before 2007 Scotland was governed for eight years by a Labour-Liberal Democrat coalition. Similarly in Wales there have been periods of minority Labour government, a Labour-Liberal Democrat coalition and a Labour-Plaid Cymru coalition.

In Northern Ireland a fully proportional system, Single Transferable Vote (STV), is used to elect the assembly. Until January 2017, when the power-sharing executive collapsed owing to internal disagreement, the first minister and four other members were drawn from the largest party, the

Democratic Unionist Party; the deputy first minister and three others were from the second-largest party, Sinn Fein; and one post was held by an independent. From 2011-16 three smaller parties supplied some members of the executive. It would thus be fair to describe the regions of the UK as having multi-party systems.

Strengths, Weaknesses, Opportunities, Threats Facing UK Political Parties



Current strengths


Britain’s party system is stable, and the main parties generally provide coherent platforms consistent with their ‘brand’ and ‘image’, despite the party cleavages caused by the Brexit issue (see above).


Britain’s political parties continue to attract competent and talented individuals to run for office.

Entry conditions vary somewhat by party, but it is not difficult or arduous to join and influence the UK’s political parties. Labour initially opened up the choice of their top two leadership positions to a wider electorate using their existing trade union networks and a £3 ‘supporter’ scheme (in 2015), but later reverted to full members only voting, after tensions with the party’s MPs.

All the main parties (except perhaps UKIP) have recruited across ethnic boundaries, helping to foster the integration of black and ethnic minority groups into the mainstream of UK politics.


Labour has involved a wider set of ‘supporters’ in its affairs and used digital campaigning more. And the separate group Momentum has helped channel back disillusioned, left-leaning people who had left the party under Blair and Brown, and younger people into ‘parallel’ Labour involvements through both ‘clicktivist’ and more ‘old school’ activism.


The UK’s main political parties are not over-reliant on state subsidies and can generally finance themselves either through private membership fees, individual donation and corporate donations, or (in Labour’s case) trade unions funding.


In the restricted areas where it can regulate the parties, the Electoral Commission is independent from day-to-day partisan interference.







Future opportunities


Before the 2016 Brexit vote the UK seemed to be historically evolving towards multi-party politics, a trend that also found expression in elections beyond Westminster and English local government. New and ‘outsider’ parties strengthened anti-oligopoly tendencies. Since then, however, public opinion showed a renewed emphasis upon top two-party competition.


Some strong ‘new party’ trends have emerged towards broadening involvements using digital means and extended outreach/lowered barriers to membership within Labour and the SNP. These developments could strengthen party ties with civil society, reversing years of weakening. Alternatively these effects may ebb away again .


Digital changes also open up new ways in which parties can connect to supporters beyond their formal memberships and increase their links to and engagement with a wider range of voters. Parties now generally conduct their leadership elections using an online system which makes it easier to register a preference. Other matters of internal party business and campaigns could soon be affected, potentially including setting policy.


The advent of far greater ‘citizen vigilance’ operating via the web and social media like Twitter and Facebook creates a new and far more intensive ‘public gaze’ scrutinising parties’ internal operations. Tools such as ‘voting advice’ application apps or the Democratic Dashboard also allow voters to access reliable information about elections and democracy in their area – information that neither government nor the top parties has so far either been able or willing to provide.


All the UK’s different legislatures (Westminster, and the devolved assemblies/parliaments in Scotland, Wales, Northern Ireland, and London) have now sustained coalition governments of different political stripes and at different periods, and each has operated stably. Therefore, the UK’s adversarial political culture does not rule out cross-party cooperation where electoral outcomes make it necessary.



Current weaknesses

Party membership in the UK has increased from a low base in 2010, but it is still low. Around 950,000 people are party members, out of a population of 65.6 million, with Labour and the SNP both showing strong recent growth. Conservative membership is now perhaps the most elderly of all the parties and remains small relative to Labour’s renewed mass membership.

Plurality rule elections privilege established major parties with strong ‘safe seat’ bastions of support, at the expense of new entrants. The most active political competition thus tends to be focused on a minority of around 120 marginal seats, with policies tailored to appeal to the voters therein.

It is fairly simple to form new political parties in the UK, but funding nomination fees for Westminster elections is still costly. And in plurality rule elections new parties with millions of votes may still win no seats, as happened to UKIP in 2015. At local level, some one-party dominant areas also produce councils with no opposition councillors at all.

Labour has had long-running difficulties with allegations of anti-semitism amongst some party members in recent years. Some critics argue that the Conservatives have failed to tackle Islamophobia within their ranks.

Most mechanisms of internal democracy have accorded little influence to their party memberships beyond choosing the winner in leadership elections. Jeremy Corbyn claims to be counteracting this and listening more to his members. However, in consequence, Labour struggled to delineate the relationship between MPs in the parliamentary party (who MPs saw as not answerable to voters) and the enlarged membership (who may not reflect Labour voters’ views well). These tensions eased in 2017.

There are large inequities in political finance available to parties, with some key aspects left unregulated. These may distort political (if not) electoral competition. Majority governments can alter party funding rules in directly partisan and adversarial ways.

The ‘professionalisation of politics’ is widely seen as having ‘squeezed out’ other people with a developed background outside of politics (but see below).

Future threats


Critics argue that the cross-cutting of both the top two parties by Brexit positions means that party labels and identities are no longer effectively structuring (but instead obscuring) the dominant issues in UK politics.



In multi-party conditions, plurality rule elections for Westminster may operate in ever more eccentric or dramatic ways, as with the SNP’s 2015 landslide in Scotland almost obliterating every other party’s MPs there. The SNP’s strong support in 2014–16 threatened to create a ‘dominant party system’ system in Scotland, where party alternation in government ceases for a long period. However, this prospect soon receded with both Tory and Labour revivals north of the border.

The growth of political populism and identity divisions post-EU referendum has ‘hollowed out’ the centre ground of British politics, with the Liberal Democrats unable to regain their earlier momentum.

Moves by governing political parties to alter laws, rules and regulations so as to skew future political competition and disadvantage their rivals can set dangerous precedents that degrade the quality of democracy. The Conservative government changes to electoral registration and redrawing of constituency boundaries may all have such effects, even if implemented in non-partisan ways.





2018 Audit of UK Democracy, Patrick Dunleavy and Sean Kippin