Variations of this have circulated among Irish and left-wing Eurosceptic groups. Delors explicitly denied making any such statement in 1992 and 1998 in the leadup to Irish referendums on the Maastricht and Amsterdam treaties. Commentators have found no evidence for it.
Attributions:
[Facing the threat of Brussels rule at our expense, https://www.irishtimes.com/newspaper/archive/1991/1121/Pg014.html#Ar01400, 30 July 2019, The Irish Times, 21 November 1991, 14, subscription, Anthony, Coughlan]
[Proinsias, de Rossa, https://www.oireachtas.ie/en/debates/debate/dail/1991-11-29/3/#para_191, 29 November 1991, Dáil Éireann debates, Maastricht Summit: Motion]
[Maastricht and neutrality : Ireland's neutrality and the future of Europe, John, Maguire, Joe, Noonan, 1992, Cork, People First/Meitheal, 19–20]
[Fox, Carol, Gearing up, 25554848, Fortnight, 1994, 334, 11–12: 12, 0141-7762]
[Joe, Higgins, https://www.oireachtas.ie/en/debates/debate/dail/1997-10-16/24/#para_608, 16 October 1997, Dáil Éireann debates, Amsterdam Treaty: Statements (Resumed)]
Edward, Spalton, 4 July 2004, (Letter) Fashion statement, Daily Telegraph https://www.telegraph.co.uk/comment/letters/3608033/Fashion-statement.html,
John, Boyd, Campaign Against European Federalism, Europe for Peace Conference, Manchester, 5 March 2005 https://web.archive.org/web/20070809083941/http://www.gmdcnd.org.uk/events/europeconference/amC.htm,
[Gibson, Dirk C., Commercial Space Tourism: Impediments to Industrial Development and Strategic Communication Solutions, 2012, Bentham Science Publishers, 9781608052394, 12, https://books.google.ie/books?id=hSkW9TW3omEC&pg=PA12, 21 July 2019]
The European Alliance of EU-critical Movements, EU Counter Summit Statement, London, 7 November 2015 http://teameurope.co/statements.html,
[The financial cost of signing up to PESCO, https://people.ie/news/PN-178.pdf, People's News, People's Movement, Dublin, 178, 20 December 2017]
Morning Star, Macron calls for joint EU army project to step up a gear, 27 August 2018 https://morningstaronline.co.uk/article/macron-calls-joint-eu-army-project-step-gear,
Refutations:
The Irish Times, subscription, 12 June 1992, 12, Colm, Boland, 'Interference' by Delors denounced https://www.irishtimes.com/newspaper/archive/1992/0612/Pg007.html#Ar00701,
[30001811, Ireland's Foreign Relations in 1992, Patrick, Keatinge, Irish Studies in International Affairs, 4, 1993, 72 [footnote]]
McKenna's case not a Euromyth, 15 May 1998, Patrick, Smyth, The Irish Times https://www.irishtimes.com/news/mckenna-s-case-not-a-euromyth-1.152890,
Misattributed