SF

Sinn Féin

NI Leader: Michelle O'Neill — First Minister of Northern Ireland
▲ NI Poll Leader — Historic First
28%
NI Polling (2026)
27
Stormont MLAs (2022)
7
Westminster MPs (abstentionist)
1st
Largest NI party since 2022

Sinn Féin Northern Ireland: Polling History

▲ First nationalist party to lead NI polls
Historic milestone: When Sinn Féin topped the 2022 Stormont Assembly election with 27.9%, it became the first time a republican-nationalist party had won a Northern Ireland election since the state was created in 1921. Michelle O'Neill became the first nationalist First Minister in NI history in February 2024.
Election / DateSinn Féin % (NI)SeatsKey Context
2003 Stormont Assembly23.5%24 MLAsSF surpasses SDLP as largest nationalist party
2007 Stormont Assembly26.2%28 MLAsSt Andrews Agreement; SF enters Executive with DUP
2017 Stormont Assembly27.9%27 MLAsRHI scandal triggers election; SF collapses Executive over Arlene Foster
2019 General Election (NI)22.8%7 MPs7 abstentionist MPs; Brexit referendum context
2022 Stormont Assembly27.9%27 MLAsFirst SF Stormont election win — historic; First Minister right triggered; DUP blocks for 2 years
2024 General Election (NI)24.5%7 MPsHolds 7 Westminster seats; continues abstentionism
2025–2026 (NI polls)28%Sustaining lead; Michelle O'Neill as First Minister consolidates nationalist politics

The Island-of-Ireland Context: SF North and South

An all-island party: Sinn Féin is the only major party that contests elections in both Northern Ireland and the Republic of Ireland. Its simultaneous breakthrough in both jurisdictions between 2020 and 2022 was the most significant political development on the island of Ireland in decades.

Northern Ireland — In Government

Sinn Féin Michelle O'Neill serves as First Minister of Northern Ireland since February 2024 — the first nationalist First Minister in NI history. The party holds 27 MLAs and multiple Executive ministries. SF strategy focuses on delivering in government while maintaining its long-term Irish unity agenda.

Republic of Ireland — In Opposition

In the 2020 Republic election, Sinn Féin topped the poll on first preferences with 24.5% — but Fianna Fáil and Fine Gael formed a coalition excluding SF. In the November 2024 Republic election, SF fell back to around 24% and again found itself in opposition. It is the largest opposition party in the Dáil, led by Mary Lou McDonald.

Michelle O'Neill: First Nationalist First Minister

Path to First Minister

Michelle O'Neill was elected to the Stormont Assembly in 2007 for Mid Ulster and rose through SF ranks as a pragmatic, moderate voice. She succeeded Martin McGuinness as NI party leader in 2017. When the DUP returned to Stormont in February 2024, O'Neill was nominated as First Minister — the first nationalist or republican to hold the post.

Leadership Style and Strategy

O'Neill has worked to present Sinn Féin as a mainstream governing party rather than a movement defined by its republican past. She has reached out to unionist communities, attended events with the British Royal Family, and emphasised practical service delivery over constitutional rhetoric in her day-to-day politics.

United Ireland: Where Does the Polling Stand?

Not there yet — but a live debate: Support for a united Ireland in Northern Ireland typically polls between 28–35% among those who express a preference. The key metric is don't know voters (20–25%) and those who describe themselves as neither unionist nor nationalist — where the argument for unity will ultimately be won or lost.
Survey YearUnited IrelandRemain in UKDon't KnowKey Finding
2014~17%~63%~20%Pre-Brexit baseline; firm unionist majority
2016 (post-Brexit)~21%~58%~21%Brexit vote shifts opinion; NI voted 56% Remain
202130–35%45–50%20–25%Some polls show near-parity; spike reflects Protocol anger
2023–202428–32%48–52%20–22%Settled back from peak; firm unionist majority remains
2025–2026~30%~50%~20%Long-term trend upward; border poll not imminent but on political agenda

Sinn Féin Key Policy Positions (Northern Ireland)

Irish Unity

Core long-term objective. Campaigns for a planned and orderly border poll in both NI and the Republic, with a coordinated all-island constitutional conversation beforehand.

Abstentionism at Westminster

Sinn Féin MPs are abstentionists: they take the seats but do not take their seats in the House of Commons, in keeping with a policy held since the party founding. This means NI loses 7 votes in Westminster parliamentary divisions.

Windsor Framework

SF broadly accepts the Windsor Framework as the best available arrangement for NI and advocates for further EU alignment rather than less.

Social Policy

Supports same-sex marriage, abortion rights, and progressive social policies — a significant shift from SF historically conservative Catholic social positioning, reflecting a modernisation under Mary Lou McDonald and Michelle O'Neill.

Irish Language

Strongly supports the Irish Language Act (New Decade New Approach commitments) and the promotion of Irish as a community language in NI.

Public Services

As a governing party in NI, SF focus is on health waiting lists (the worst in the UK), housing supply, and childcare. Performance as a governing party is increasingly central to making the case for SF-led government.

Who Votes Sinn Féin? Demographics

Generational shift: Sinn Féin strength is concentrated among younger voters, Catholics, urban Belfast residents, and those who describe themselves as “Irish” rather than “British” or “Northern Irish.” The party has also gained ground among voters who are neither traditionally nationalist nor unionist but who back Sinn Féin on practical service delivery and social policy.
Demographic GroupSinn Féin SupportKey Driver
18–34 (all backgrounds)~35%Social liberalism; housing; EU alignment
Catholic background~55%Community identity; historical nationalist tradition
Greater Belfast (West/North)40–55%Republican heartland; community infrastructure
Border counties (South Armagh, Derry)~45%Strong republican identity; cross-border ties
Middle-class professionals (Catholic)~38%Social policy; EU; pragmatic unification argument
Protestant background~3%Unionist identity; Westminster abstentionism a barrier
Over-65s~22%Weaker than with younger generations; older voters more likely to identify firmly unionist or nationalist

Frequently Asked Questions

Why don’t Sinn Féin MPs take their seats at Westminster?

Sinn Féin’s abstentionist policy means its elected MPs refuse to take the oath of allegiance to the British Crown required to sit in the House of Commons. This policy has been maintained since the 1918 general election, when SF won 73 seats but refused to attend Westminster, instead forming a breakaway Irish parliament (Dáil Éireann) in Dublin. The party’s 7 current Westminster MPs represent real constituencies but cast no votes — meaning Northern Ireland is significantly under-represented in parliamentary divisions.

Is Sinn Féin the same party north and south of the border?

Yes. Sinn Féin is a single all-Ireland political party with one leadership structure. Mary Lou McDonald is the overall party president and leads the Dáil opposition in Dublin. Michelle O'Neill leads the NI section and serves as First Minister. Both report to the same party structures — an arrangement unique among parties that contest elections in both jurisdictions.

What was the IRA’s relationship with Sinn Féin?

Sinn Féin was historically the political wing of the Provisional IRA. The IRA declared a ceasefire in 1994 and decommissioned its weapons in 2005 under international verification. SF now firmly rejects political violence as a strategy and participates fully in democratic institutions in both NI and the Republic. The Troubles legacy remains politically sensitive, particularly around victims’ issues and the Legacy Act 2023.

When could a border poll on Irish unity take place?

Under the Good Friday Agreement, the Secretary of State for Northern Ireland must call a border poll if they believe a majority would vote for unity. There is no fixed numerical trigger in the GFA itself. Most analysts believe a poll remains unlikely within the next decade: current NI polls show approximately 30% support for Irish unity, compared to 50% for remaining in the UK and 20% don’t know. The don’t know cohort is where the outcome of any future poll would ultimately be decided.

Why did Sinn Féin not enter government in the Republic of Ireland in 2020?

In the 2020 Republic election, Sinn Féin topped the poll on first preferences with 24.5% — a historic result. However, Fianna Fáil and Fine Gael, the two traditional centre parties, formed a coalition with the Greens that explicitly excluded SF. Critics argued this was anti-democratic given SF’s electoral mandate; the government argued it had policy and governance differences. In the 2024 election, SF again came third and remained in opposition.

What are Sinn Féin’s main priorities in the Northern Ireland Executive?

Sinn Féin’s Executive priorities include reducing NHS waiting lists — Northern Ireland has the worst in the UK, with some patients waiting over three years for treatment — expanding affordable childcare, increasing housing supply, and implementing Irish Language Act provisions. Michelle O'Neill has consistently emphasised cross-community service delivery, reaching out to unionist communities and attending events that would previously have been politically impossible for a Sinn Féin leader. The party’s governing record is central to its long-term argument that a Sinn Féin-led all-Ireland government would be competent and inclusive.

Explore More

Video: Further Analysis

Video: The state of all UK political parties in 2026 — from Reform UK's surge to Labour's collapse, with context on where each party stands ahead of 2029.

LIVE
Voting Intention Reform UK26% Labour20.8% Con19.4% Greens13% Lib Dems12.2% Starmer Approval Approve18% Disapprove61% VI Tracker Leader Approval GE2029 Forecast Reform UK Rise Latest Analysis