"Rydyn ni wedi rhybuddio ar sawl achlysur na all y Deyrnas Unedig gymryd y risg economaidd anferthol o dorri'n rhydd o'r Farchnad Sengl a'r Undeb Tollau. Mae hyn yn arbennig o wir am y sectorau gweithgynhyrchu a gwasanaethau arbenigol sydd mor bwysig yng Nghymru wrth iddyn nhw ddarparu swyddi sy'n cynnig cyflogau uchel ar gyfer sgiliau ar lefel uchel.
“We have repeatedly warned that the UK cannot take the huge economic risk of cutting ourselves adrift from the Single Market and Customs Union. This is particularly true for manufacturing sectors and specialist services, which in Wales are so important in providing high-paid, high-skilled jobs.