The Alliance Party of Northern Ireland (APNI) is a liberal and centrist political party in Northern Ireland.

Founded in 1970, the party promotes efforts to overcome traditional unionist-nationalist divisions, and designates as “Other” in the Northern Ireland Assembly. Alliance is aligned with the Liberal Democrats in Great Britain.

Naomi Long MLA has served as leader of the Alliance Party since October 2016. The party has experienced a significant surge in support in recent years, establishing itself as the third-largest party in Northern Ireland.

At the 2022 election to the Northern Ireland Assembly, the Alliance won 17 seats and 116,681 votes (13.5%). This marked a gain of eight seats compared to its 2017 performance, when the party had ranked only fifth-largest in the assembly.

House of Commons: Alliance won one seat and 117,191 votes (15.0%) at the 2024 general election. Sorcha Eastwood was elected as the Alliance MP for Lagan Valley – the first non-unionist to be elected to represent the constituency.

Northern Ireland Assembly: The party won 17 out of 90 seats in the 2022 Northern Ireland Assembly election.

Local government: The Alliance Party won 67 councillors (out of 462 council seats across 11 districts) in the 2023 Northern Ireland local elections, establishing itself as the third largest party in Northern Ireland local government.

Who is the leader of the Alliance Party?

Naomi Long is the current leader of the Alliance Party. She previously served as the party’s deputy leader from 2006 to 2016.

Long succeeded David Ford as Alliance leader in October 2016. She is the longest-serving leader of the main Stormont parties.

A former lord mayor of Belfast (2009-2010), Long served as an MP for Belfast East from 2010 to 2015 and an MEP for Northern Ireland from 2019 to 2020. She has represented Belfast East in the Northern Ireland Assembly since 2020.

Long currently serves as minister of justice in the Northern Ireland executive. She first took up this position in January 2020.

The party’s deputy leader is Eóin Tennyson, who has represented Upper Bann in the Assembly since 2022. Born in May 1998, Tennyson is the youngest member of the NI Assembly. Tennyson defeated Kate Nicholl in the 2024 Alliance deputy leadership election.

Lord (John) Alderdice, the first speaker of the Northern Ireland Assembly, led the party from 1987 to 1998. David Ford, who led the Alliance from 2001 to 2016, served as Northern Ireland’s first-ever minister of justice in the post-Good Friday Agreement era. Ford held this post from 2010 to 2016.

What does Alliance stand for?

The Alliance Party’s foundational principle is the promotion of a united community in Northern Ireland.

A recent version of the party’s constitution described its overriding objective as seeking to “heal the bitter divisions in our community”.

The party is neutral on the constitutional status of Northern Ireland, arguing that the issue should not be the dominant basis of politics.

A liberal, centrist party, it is a member of the Liberal International and the Alliance of Liberals and Democrats for Europe party.

In the foreword to her party’s 2024 general election manifesto, Long described the incumbent Conservative government as “negative” and “destructive”.

The party’s primary constitutional aim is the reform of Northern Ireland’s political institutions, as established under the Good Friday Agreement. Alliance representatives campaign to end the NI Assembly’s mandatory power-sharing executive and the associated community designation framework.

Alliance’s 2024 general election manifesto called for reform of the NI Assembly and executive “so no one party can hold us all to ransom.” The party suggested that the current framework embedded “institutional sectarianism”.

Alliance was strongly opposed to Brexit and has since campaigned for a closer relationship between the UK and the EU. It viewed the Windsor Framework, negotiated by Rishi Sunak as prime minister, as a means to manage the negative impacts of Brexit.

The Alliance argues that “Brexit was and continues to be fundamentally destructive for the UK as a whole.”

The party has expressed support for a “green new deal to decarbonise our economy, protect workers, tackle fuel poverty, and create thousands of jobs.”

In March 2025, Long announced that Alliance representatives would not attend St Patrick’s Day events at the White House. She cited a lack of respect for the US President, Donald Trump.

Long said: “To be clear, I respect the right of US citizens to elect whomever they wish as president. I also respect the office of president. However, I do not and will make no pretence of respecting the current office-holder.”

Alliance and the Liberal Democrats

The Alliance Party of Northern Ireland is aligned with Liberal Democrats.

The party’s former leader, Lord Alderdice, took the Liberal Democrat whip on non-Northern Ireland issues in the House of Lords upon being elevated to the peerage in 1996. From 2010 to 2014, Alderdice served as convenor of the Liberal Democrats in the House of Lords.

There is a separate Liberal Democrat local party operating in Northern Ireland, known as the Northern Ireland Liberal Democrats. David Ford, another former Alliance leader, was a member of both the Alliance Party and the Liberal Democrats.

Who votes for the Alliance Party? (Demographics of support)

The following data is drawn from the 2022 Northern Ireland Life and Times (NILT) survey conducted by ARK, regarding first preference votes in the 2022 assembly election.

Age: The Alliance Party won 34% of the vote among those aged over 65 at the 2022 NI assembly election. It performed similarly strongly among voters in the age brackets 55-64 (28%), 45-54 (32%), and 35-44 (31%). In all these age brackets, Alliance won the highest share of the vote.

Alliance won 17% of the vote among 18-24 year olds, where it was outperformed by Sinn Féin.

Gender: Alliance won 28% of the vote among women and 29% of the vote among men at the 2022 NI Assembly election, according to the NILT survey.

Religion: The Alliance Party draws its strongest support from those identifying with no religion. In total, Alliance secured 48% of the vote among those with no religion.

Among both Protestant and Catholic voters, the party won 22% of the vote respectively. This pattern made Alliance the only major party with such balanced support from the two main religious communities in Northern Ireland.

History and emergence as a significant force

The Alliance Party of Northern Ireland (APNI) was formally established on 21 April 1970. The party grew out of the New Ulster Movement, formed on 5 February 1969 – a group that espoused moderate unionism and inclusive, cross-community reforms in response to the Northern Ireland civil rights movement.

The party’s “New Ulster” roots referred to the moderate unionism espoused by Terence O’Neill, who served as Northern Ireland prime minister from March 1963 to April 1969.

Indeed, the New Ulster Movement was formed to support O’Neillite candidates at the February 1969 Northern Ireland general election – the main feature of which was the fragmentation of the ruling Ulster Unionist Party (UUP) between supporters of the serving PM’s reform programme and its vehement opponents.

The Alliance Party’s founding members were mostly moderate unionists, therefore, including former members of the UUP.

Upon its founding, the new party issued an inaugural manifesto, entitled Declaration of Intent – A new Political Chapter, which repudiated the Unionist and Nationalist parties “for whom the clock stopped in 1920” as well as the Labour and Liberal parties “who have palpably failed to restart that clock”.

Specifically, the Alliance highlighted the UUP’s “divisive and undemocratic link with the Orange Order” as proof that the party “could not and cannot create a united and harmonious community.”

The party also repudiated the Nationalist Party for having “merely served to perpetuate existing community divisions” and failing to act as a “responsible opposition.”

The Alliance declared: “We say to all these parties – ‘A plague on all your houses’. The people of Northern Ireland will tolerate your blindness no longer; they will not stand by and see you despoil the next fifty years as you have wasted the first fifty.”

The declaration set out four principles upon which the new Alliance Party of Northern Ireland would be founded. The first sought to reconcile support for the UK with a demand for civil rights, arguing that the Union is “in the best economical and social interest of all citizens.” Critically, the party argued that the Union implied “British standards of democracy and social justice”, which must be “energetically secured and steadfastly upheld.”

In early 1972, three members of the Northern Ireland House of Commons defected to the Alliance Party, namely Bertie McConnell, an independent Unionist; Phelim O’Neill of the UUP; and Tom Gormley, who sat as an independent nationalist. This institutional foothold was short-lived, however. The Stormont parliament was suspended and direct rule imposed mere weeks later.

In 1973, the Alliance Party won its first MP at Westminster after Stratton Mills defected from the UUP. But this too was short-lived; Mills stood down at the February 1974 general election.

The Alliance Party participated in the Sunningdale Agreement negotiations in 1973, which led to Northern Ireland’s first power-sharing executive. In the elections that followed the agreement, the party won 9.2% of the vote and eight seats. Alliance leader Oliver Napier held the office of minister for law reform in the ill-fated executive.

In 1977, the Alliance Party reached its highest electoral standing since its founding when it won 14.3% of the vote.

In June 1998, the party won 6% of the vote and six seats in the new Northern Ireland assembly created by the Good Friday Agreement.

During the 1990s, the Alliance Party shifted towards a neutral stance on Northern Ireland’s constitutional status.

In 2010, Naomi Long became the party’s first elected MP, winning the Belfast East seat from the Democratic Unionist Party (DUP) incumbent, Peter Robinson.

Support for Alliance increased markedly in the late 2010s.

The party won 78,052 votes (11.5%) in the 2019 Northern Ireland local elections. This result was described as the “Alliance surge”. At the same time, in the European Parliament elections, Alliance won its first MEP.

In the general election later that year, Long’s Alliance won 134,115 votes (16.8%) and one seat.

The party benefited from opposition to Brexit and popular frustration with paralysis at Stormont.

In 2022, the party more than doubled its seats in the assembly election to become the third-largest party for the first time, leapfrogging both the Social Democratic and Labour Party (SDLP) and the UUP.