A UK Supreme Court ruling has reduced the likelihood of EU legal intervention in Northern Ireland over definitions of biological sex. Jim Allister, leader of the Traditional Unionist Voice, said the Dillon judgment limits the reach of Article 2 of the Windsor Framework.

The ruling addressed the Legacy Act 2023 and found no conflict with the Windsor Framework. Allister had previously expressed concern that the EU could use Article 2 to challenge the UK Supreme Court's definition of "woman" as limited to biological females.

Allister warned that EU involvement might create differences in rights between Northern Ireland and the rest of the UK. He noted that a recent Court of Justice of the EU decision against Hungary had raised the possibility of similar action on gender identity matters.

Following the Dillon judgment, Allister stated that it would be more difficult for the Equality Commission and others to argue against the supremacy of biological sex. He said CJEU rulings should now offer little assistance in such cases.

Fiona McAnena, director of campaigns for Sex Matters, said the Hungary ruling does not address single-sex spaces or the rights of others. She called on the Equality Commission for Northern Ireland to state that single-sex spaces should be based on biological sex.