Bydd y Prif Weinidog yn dweud y byddai creu ffin ‘galed’ rhwng Prydain a Gweriniaeth Iwerddon, wrth i Lywodraeth y DU fynnu gadael y Farchnad Sengl a’r Undeb Tollau, yn fygythiad gwirioneddol i economïau Cymru ac Iwerddon.
The First Minister will say the creation of a ‘hard’ maritime border between Great Britain and the Republic of Ireland, because of the UK government’s insistence on leaving the Single Market and the Customs Union, would be a very real threat to the Welsh and Irish economies.