“Rydyn ni’n dal i alw ar lywodraeth y DU i roi tystiolaeth gadarn pam y byddai’n fanteisiol yn y tymor hwy i’r DU fod y tu allan i undeb tollau gyda’r UE.
“We also continue to call on the UK government to provide firm evidence on why being outside a customs union with the EU would be of advantage to the UK in the longer term.