The legal and constitutional relationship between Ireland and England (and latterly Britain) was unclear for many centuries. Although Ireland enjoyed a good deal of legislative sovereignty under Grattan’s Parliament from 1782, the Acts of Union in 1801 set up direct rule from Westminster. During the nineteenth century, there was a campaign and draft legislation for Irish Home Rule (which Dicey, an ardent unionist, vehemently opposed). This campaign is worth reconsidering in the Brexit/Scottish independence context, given the varied legal and constitutional arrangements that were explored and vigorously debated. However, Home Rule never came about, rendered pointless by subsequent events. Since the Belfast/Good Friday Agreement and devolution in 1998, Northern Ireland has a had a variegated but pragmatic settlement of consociation and compromise quite different from the traditional British constitutional settlement. The EU has played its role in the peace process, providing structures for its continuation. Brexit now presents considerable challenges for Northern Ireland and the Republic.