evidence: BESES figures for goods and services in 2016 show that 35% of the total turnover of Northern Ireland businesses was sold outside Northern Ireland. Of these total sales, the majority (58%) went to Great Britain whereas the remaining 42% were exported to the rest of the world, therefore in 2016 Great Britain continued to be the most important market for businesses located in Northern Ireland. Sales to Great Britain were worth one and a half times the value of all Northern Ireland exports and nearly four times the value of exports to the Republic of Ireland in 2016. However, the sale of finished products to Great Britain relies upon cross-border trade in raw materials and components through integrated supply chains, meaning trade with both Great Britain and the Republic of Ireland are vital to Northern Ireland’s economy (NISRA, 2018). We estimate the extent of supply-chain interdependencies between Northern Ireland and the Republic of Ireland in Section 6 but acknowledge that further research is needed to investigate supply-chain linkages between Northern Ireland and Great Britain.