O ran y negodiadau, cydnabu’r Prif Weinidog sylwadau diweddar Llywodraeth y DU mewn perthynas â’i hymrwymiad parhaus i Gonfensiwn Sewel a phwysodd arni i ymestyn yr egwyddor hon i’r negodiadau sydd ar fin cael eu cynnal rhwng y DU a’r UE. Eglurodd y byddai ymrwymiad clir i gynnwys y Gweinyddiaethau Datganoledig yn cryfhau sefyllfa’r DU yn y negodiadau mewn gwirionedd. Er bod rhai cynigion wedi cael eu gwneud mewn perthynas â strwythur y negodiadau, roedd angen mwy o waith ar hyn, ac roedd angen i Lywodraeth y DU gytuno ar frys i’r egwyddor o beidio â bwrw ymlaen, fel arfer, heb gytundeb y Llywodraethau Datganoledig mewn perthynas â materion datganoledig
On negotiations, the First Minister acknowledged the UK government’s recent comments with respect to their continued commitment to the Sewel convention and pressed them to extend this principle to the forthcoming UK-EU negotiations. He pointed out that a clear commitment to involving the devolved governments would actually strengthen the UK’s hand in the negotiations. While some proposals had been made as to a structure for the negotiations, this needed further work and the principle of not normally proceeding without the agreement of the devolved governments in relation to devolved matters needed to be agreed urgently by the UK government.