Bydd Mark Drakeford yn dweud wrth Theresa May bod dyletswydd foesol arni i sicrhau na fydd y DU yn cael ei rhwygo allan o'r UE heb gytundeb, gan roi ysgytwad difrifol i holl economi Cymru a bygwth swyddi a busnesau ym mhob cwr o'r wlad.
Mark Drakeford will tell the Prime Minister she has a moral obligation to prevent the UK crashing out of the EU, which would have seismic repercussions for the whole of the Welsh economy and threaten jobs and businesses throughout Wales.