Llywodraeth y DU sydd â’r cyfrifoldeb am reoli ffiniau’r DU. Drwy gydol y broses, mae Llywodraeth Cymru wedi ceisio bod yn adeiladol i alluogi Llywodraeth y DU i gyflawni ei hamcanion polisi. Mae Llywodraeth y DU wedi rhannu ei methodoleg gyda ni ac mae’r fethodoleg hon wedi’i hadolygu gan y Prif Swyddog Meddygol.
Responsibility for managing UK borders rests with the UK Government.  The Welsh Government has, throughout this process, aimed to be constructive in enabling the UK Government achieve its policy objective.  The UK Government has shared its methodology with us and this has been reviewed by the Chief Medical Officer.