Both the UK and the Republic of Ireland joined the European common market in 1973. 80 percent of Irish exports transits through Britain. But with the UK formally leaving the EU on Friday, many in Ireland are still in the dark on how it'll affect businesses. There's talk of the 'Irish Protocol', but no one seems to know if that means checks and tariffs on goods moving from the UK into Northern Ireland. As Iolo ap Dafydd reports, there are concerns about how trade will be regulated with Northern Ireland like Britain outside the EU - and the Republic of Ireland still a member.