evidence: Movement between Ireland and the UK now [...] In the same month, Theresa May said: "Just as it would be unacceptable to go back to a hard border between Northern Ireland and Ireland [after Brexit], it would also be unacceptable to break up the United Kingdom’s own common market by creating a customs and regulatory border down the Irish Sea." She described this as her "personal commitment". [...] This is because if there is no EU-UK agreement on free trade in goods, there would be some British taxes on imports from Ireland, and vice versa.