evidence: When I composed "A History of Ireland in 100 Euphemisms" here some years ago, one of the terms I didn't have room for was "Foyleside". Describing the area where the river Foyle meets the sea, it's a politically correct alternative to the disputed names of the local city, and much easier than saying "Derry-stroke-Londonderry". Hence Foyleside Shopping Centre, Radio Foyle, the Foyle constituency, and so on. Rarely has a natural feature so dominated the nomenclature of an urban environment. [...] But as I had somehow forgotten until the Democratic Unionist Party reminded us this week, Lough Foyle is itself disputed territory, and has been since partition. The UK claims it fully, up to and including the foreshore on the Donegal side. Ireland rejects this, asserting a counterclaim. And although both jurisdictions have somehow muddled through on the issue for a century, it now threatens to become yet another complication in the event of a hard Brexit. A local version of the Cod War is unlikely: most cod occurs inland in Northern Ireland, where it often coincides with shoals of underemployed politicians. But what is already happening on Lough Foyle, seafood-wise, is a huge increase in oyster-farming. [...] Lough Foyle was always more complicated, however.