Dr. Martina Lawless:

The IFAC has not done a direct analysis on Brexit but work has been done by the ESRI and InterTradeIreland with the enterprise agency in Northern Ireland, which shows Northern Ireland firms to be considerably more exposed than firms in the rest of the UK. It shows pretty significant decreases in trade. The impact is felt in particular by small firms that do frequent but relatively low-value transactions across the Border, so the impact on the number of firms trading is a lot more substantial than the impact on the value of trade.

That analysis did not look at a cliff-edge major distortion such as, for example, major checks on the Border; it merely considered the impact of tariffs. Given the high degree of uncertainty currently, such as whether there will be a backstop or separate treatment for Northern Ireland and whether the UK will stay in the customs union for a significant amount of time, it is difficult to come up with an estimate based on any degree of precision about how it would impact, other than to get a sense of the ordering of priorities, whereby those firms in Northern Ireland will be more exposed than elsewhere. The exact magnitude of the effect is not really possible to estimate.