A Ministerial briefing note released to Gript Media under freedom of information legislation states that the wording of the comprehensively defeated Article 41.2 “Care” amendment to the Constitution was designed to avoid placing into the Constitution “a concrete and mandatory obligation to provide support.”

The release of the Department of Finance records prompted No campaigner Senator Michael McDowell to accuse the Coalition of having misled voters.

Ministers had also insisted there were no taxation or immigration implications. But files showed officials grappling with tax issues and legal advice that said greater weight would be given to non-marital family rights “in childcare, immigration and social welfare”.

Mr McDowell said Government spokespersons “consistently misrepresented the substance of the legal advice that they were receiving from the AG and elsewhere [including apparently outside counsel]”.

“They attempted to minimise or deny any practical implications for succession law, taxation law, immigration law, welfare law and childcare in a manner that the documentation proves was misleading.”

Mr O’Gorman’s spokesman said: “The Minister rejects that assertion.”