EU Referendum - The Border Lands Separating Northern And Southern Ireland

UNSPECIFIED, IRELAND - MAY 04: A welcome to Northern Ireland road sign signalling the crossing of the border between north and south can be seen on May 4, 2016 in Ireland. The United Kingdom has just one external land border which is located between Northern Ireland and the Republic of Ireland. At present there are no checkpoints in place for anyone crossing this border, either by foot or vehicle. Prior to the Anglo-Irish agreement anyone wishing to cross the border was subjected to armed checkpoints while unguarded country roads were blocked by concrete barricades. With the Brexit referendum taking place on June 23 to decide whether Britain should remain in the European Union some politicians have warned that the open border could be used as a possible backdoor entrance by migrants, traffickers and criminals wishing to gain access to the UK following a decision to leave the EU. (Photo by Charles McQuillan/Getty Images)