Think about it. Every time you enter Dublin from an airport in Britain, you have to show your passport, whether you are British or Irish or some other EU citizen. In law, only British or Irish citizens are allowed free travel between the islands, but you have to show your passport anyway. In Belfast, nothing. There’s a very sharp letter in the Irish Times yesterday worth quoting with regard to the fate of the Common Travel Area between Britain and Ireland. It was in response to a piece by Frank Millar, which thanks to the new design at the Times I can no longer find.
Ironically, it is the Irish authorities that have been abolishing the common travel principle in stages. About five years ago immigration control at Irish airports began stopping all passengers arriving from the UK asking them to state formally that they were British, and/or Irish citizens “normally resident” in either country. Apparently, only such people are entitled to common travel. More recently, they have insisted that all passengers must present a valid British or Irish passport to prove they are entitled to “passport-free” entry into Ireland.
When I asked an airport immigration officer if I needed a passport to walk a dog on my family estate, which straddles the Border, she insisted that the immigration service would be fully entitled to refuse me re-entry into the part of the estate in Co Monaghan if we had strolled passport-less into Co Armagh. This applies to overseas visitors on riding holidays on the estate, who never had any entitlement to the common travel provisions in the first place. She further cautioned me that Gordon Brown was about to definitively end the common travel area.[emphasis added]