2000 AD, Chinese woman was staying in Wales, got pregnant, got a plane to Northern Ireland which didn’t need a visa as it is in the UK, gave birth, claimed the child was a citizen of the Republic of Ireland which isn’t a part of the UK

(there’s a lot of history, basically babies born in Northern Ireland at this point were entitled to Irish citizenship as well as babies born in the Republic of Ireland regardless of parents nationality, most people in Northern Ireland are entitled to dual citizenship between the UK and ROI)

Moved back to Wales, told the Home Office she was entitled to stay in the UK because under EU law, she was permitted to stay to take care of her child who is an EU citizen despite her not being an EU citizen.

Law was changed so that it only applies to children of Irish parents, grandparents or born before 2005 in Ireland or Northern Ireland.