T HE NEW trade frontier between Northern Ireland and the British mainland was intended as a conflict-prevention measure, allowing Great Britain to leave the European Union’s single market without reimposing a hard border between Northern Ireland and the Republic to the south. So far, not so good. Listen to this story Enjoy more audio and podcasts oniOSorAndroid. Unionist politicians, angered by disruption to shopping and trade with Great Britain, now call for the protocol that imposed a new Britain-Northern Ireland border to be scrapped. In Protestant areas of County Antrim youths rioted last month, egged on by loyalist paramilitaries. Last week Northern Ireland’s first minister, Arlene Foster, was forced to resign by her party, having reluctantly accepted the protocol as the least bad solution.