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Seamus Costello

1939 – 1977

Irish politician

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About Seamus Costello

Lived 1939 – 1977 (aged 37–38). Seamus Costello was an Irish politician.

Seamus Costello (1939 – 5 October 1977) was an Irish republican socialist, paramilitary leader, and elected politician. Born in Bray, County Wicklow, he rose to prominence in the republican movement during the Irish Republican Army's Border Campaign of the late 1950s and subsequently became one of the most significant, if divisive, figures in Irish republican politics. He is best remembered as the founder of the Irish Republican Socialist Party (IRSP) and its paramilitary wing, the Irish National Liberation Army (INLA). He remains the only leader of an Irish political party to have been assassinated.

Early life Costello was born at Old Connaught Avenue, Bray, County Wicklow, the son of John Costello, a farmer and cattle-dealer, and his wife Elizabeth. He was educated at the Christian Brothers' College, Monkstown Park. He left school at the age of 15 and worked initially as a mechanic before becoming a car salesman in Dublin.

Border Campaign and early republicanism At 16, Costello joined both Sinn Féin and the Irish Republican Army (IRA). Within a year, he was commanding an active service unit in south County Londonderry during the IRA's Border Campaign (1956–1962). His leadership ability and his burning of the courthouse in Magherafelt earned him the nickname "the Boy General". The unit's most publicised actions included the destruction of bridges.

In 1957, he was arrested in Glencree, County Wicklow, and sentenced to six months in Mountjoy Prison. On his release, he was immediately interned at the Curragh camp for two further years. He used his time in custody studying, drawing particular inspiration from the Vietnamese struggle for independence. He became a member of the escape committee, which engineered the successful escapes of Ruairí Ó Brádaigh and Dáithí Ó Conaill, among others, and later described this period as his "university days".

Costello eventually rose to the rank of Adjutant-General of the IRA. In 1964, he was sent to the recently opened Chinese embassy in Paris to seek assistance from the Chinese government for the republican movement.

Political activism After his release from internment, Costello rebuilt his political base in County Wicklow, working as Sinn Féin's local organiser. He helped found a tenants' association in Bray, and became involved in the credit union movement and various farmers' organisations. He married Maeliosa Gaynor from Rapla, near Nenagh, County Tipperary, who also became active in the republican movement. In 1966, he was elected to both Bray Urban District Council and Wicklow County Council. He was dismissed from Official Sinn Féin in 1974 after the leadership blocked his supporters from attending the party convention; his expulsion was confirmed at the ard fheis in December of that year. Despite his expulsion, Costello topped the poll in the 1974 local elections for both Wicklow County Council and Bray Urban District Council.

Founding of the IRSP and INLA On 8 December 1974, at a meeting in the Lucan Spa Hotel near Dublin, Costello presided over the founding of the Irish Republican Socialist Party (IRSP), drawing together republicans, socialists, and trade unionists. The party's declared aim was to "end imperialist rule in Ireland and establish a thirty-two county Democratic Socialist Republic, with the working class in control of the means of production, distribution and exchange" (IRSP, April 1975). At a private meeting later that same day, the Irish National Liberation Army (INLA) was established, with Costello as Chief of Staff, though its existence was initially kept secret. The new movement attracted the prominent former MP Bernadette McAliskey (Bernadette Devlin) as an early member.

Assassination On 5 October 1977, Costello was shot dead as he sat in his car on Northbrook Avenue, off the North Strand Road in Dublin. According to press reports, the gunman spoke to Costello before firing two shotgun blasts at close range, then reloaded and fired again; the gunman escaped in a waiting car. He was 38 years old and the father of four children. The Official and Provisional IRAs both denied responsibility, and Sinn Féin/The Workers' Party issued a statement condemning the killing. The INLA eventually determined that Jim Flynn, a leading member of the Official IRA, had carried out the assassination. Flynn was shot dead by the INLA on 4 June 1982, in the North Strand, Dublin, very close to the spot where Costello had been killed. No one was ever arrested or charged in connection with Costello's killing. In 2007, Wicklow County Councillor Tommy Cullen brought a notice of motion calling on the Minister for Justice to reopen the investigation, citing a 2005 article by journalist Vincent Browne. The motion did not carry, though Cullen called on Browne to bring his information to the Gardaí. At the time of his death, Costello held seats on Wicklow County Council and Bray Urban District Council, as well as memberships across a range of agricultural, trade union, cultural, and regional development bodies. He was president of Bray and District Trade Unions Council in 1976–77.

Funeral and Legacy Costello's funeral was attended by Ruairí Ó Brádaigh, president of Provisional Sinn Féin; Michael O'Riordan of the Communist Party of Ireland; Bernadette McAliskey; and local Wicklow TDs Liam Kavanagh (Labour), Ciarán Murphy (Fianna Fáil), and Godfrey Timmins (Fine Gael). Thousands attended the ceremonies in Bray. The oration was delivered by Nora Connolly O'Brien, former Senator and daughter of Easter Rising leader James Connolly, who said of Costello: "Of all the politicians and political people with whom I have had conversations and who called themselves followers of Connolly, he was the only one who truly understood what James Connolly meant when he spoke of his vision of the freedom of the Irish people."

Costello's death, according to one academic analysis, "stunted the IRSP's political growth whilst the INLA's proclivity for militarism went relatively unhindered". The loss of its founding leader deprived the IRSP of its only charismatic figurehead, and the INLA subsequently fragmented through internal feuds, eventually disbanding its armed campaign in October 2009, when a spokesperson at Costello's annual commemoration in Bray announced the organisation would pursue its objectives through peaceful and political means.

Costello remains the only leader of an Irish political party to have been killed in the history of the state.

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Important facts

Born
1939, Bray
Birth century
Occupation
Nationality
Education
C.B.C. Monkstown

People in Seamus Costello's life

Named in this biography and alive at the same time

Contemporaries

People whose lives overlapped Seamus Costello's

Frequently asked questions

Who was Seamus Costello?

Irish politician (1939-1977)

When was Seamus Costello born?

Seamus Costello was born in 1939 in Bray.

When did Seamus Costello die?

Seamus Costello died on 5 October 1977 in North Strand.

What was Seamus Costello's occupation?

Seamus Costello was a politician.

What nationality was Seamus Costello?

Seamus Costello was Irish.

Sources & further reading

· Wikipedia: Seamus Costello

· Wikidata: Q1780947

· DBpedia: Seamus Costello

Cite this page

APA: Biography.guide. (2026). Seamus Costello. https://biography.guide/seamus-costello/

MLA: "Seamus Costello." Biography.guide, https://biography.guide/seamus-costello/.

Chicago: "Seamus Costello." Biography.guide. https://biography.guide/seamus-costello/.

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