There are approximately 100 lorries per day crossing the border between Northern Ireland and Ireland, and cross-border trade represents 0.5% of UK-EU trade.
Trade across the Irish border [...] Trade across the Irish border is not simply each side selling goods to one another. A European Parliament paper notes how businesses which operate across the border "often have highly interconnected supply chains covering the island of Ireland and often involving movements across the border throughout the manufacturing process". [...] "When considering cross-border trade, it is particularly important to note the integrated nature of the agri-food sector. Food, beverages and tobacco account for 49 per cent of crossborder manufacturing trade, with, for example, more than 10,000 pigs exported from Ireland to Northern Ireland every week and a quarter of all milk produced on Northern Ireland’s farms exported for processing in Ireland."