Deirdre Theresa Costigan[1] is an Irish politician and trade unionist who has been the Labour Party MP for Ealing Southall since 2024.

[4] In 2018, Costigan was elected as a Labour councillor for the Northolt Mandeville ward of Ealing London Borough Council.

[5] She served as deputy leader of the council for the three years preceding her election in 2024 as an MP.

[7] On 18 July 2024, she made her maiden speech during a debate on foreign affairs and defence.

[4] In November 2024, Costigan voted in favour of the Terminally Ill Adults (End of Life) Bill, which proposes to legalise assisted suicide.