The leader of Northern Ireland's Democratic Unionist Party has launched a scathing attack on EU Brexit negotiator Michel Barnier.
Arlene Foster, whose party are allied with Theresa May's Conservatives in the UK parliament, told the BBC that Barnier does not understand the issues facing her country and was "not an honest broker".
Former EU commissioner and French minister Barnier is visiting Northern Ireland today as he works to resolve a deadlock over the border with Ireland in the south.
The EU, in support of Dublin, insists that there cannot be border controls between the two countries. That postion was fundamental to the establishment of the Good Friday agreement which ended decades of conflict in the north between Republicans who want to unify the Ireland and Unionists who want to remain part of the United Kingdom.
Under pressure from her own MPs, May has said the UK will not remain inside the European Customs Union, necessitating some form of border checks on goods passing between the two regimes. One solution could be that Northern Ireland takes on a different status to the rest of the UK, but that would be unacceptable to Foster's party.
"Michel Barnier's trying to present himself as someone who cares deeply about Northern Ireland and if that is the case he needs to hear the fact that we are part of the United Kingdom [and] will remain part of the United Kingdom constitutionally, politically and economically," Foster said in a BBC interview.
"Therefore his proposal of us being in an all-Ireland regulatory scenario with a border down the Irish Sea simply does not work.