BRITAIN-EU-BREXIT-IRELAND-NIRELAND-BUSINESS-GUINNESS

Locals drink Guinness at the Gap of the North pub in the border village of Jonesborough in south Armagh, northern Ireland, on October 19, 2018. - With its brown-black hue and cascading creamy head, Guinness is Ireland's most iconic export. But any post-Brexit border controls on the island of Ireland could end the free-flowing supply chain that makes the stout a staple at home and around the world. (Photo by PAUL FAITH / AFP) (Photo credit should read PAUL FAITH/AFP via Getty Images)