Currently there is some alcohol smuggling and diesel laundering across the border because of tax/price /currency differentials but it's not of a significant scale in economic terms even if it breeds a culture of lawlessness in some quarters.

I would expect, post Brexit for North south smuggling to increase significantly if there is a depreciation of Sterling and the imposition of tariffs on some products. Overall, however, the volumes are small in an EU context. It is the legal precedents and implications for general tax compliance which are likely to be most problematic.

Index of Frank's Diaries