Arlene Foster and Martin McGuinness, who took opposite sides in the British referendum on the EU, have adopted a unified approach post-Brexit in "seeking to achieve the best possible outcome for all our people".
The DUP First Minister and Sinn Féin Deputy First Minister have jointly written to prime minister Theresa May to say they were reassured by her commitment that they "will be fully involved and represented in the negotiations on the terms of our future relationships with the EU and other countries".
“We regard this as a fundamental prerequisite of a meaningful and inclusive negotiation process,” they said.
After Ms May met Ms Foster and Mr McGuinness on her first visit to Northern Ireland as prime minister last month, the Stormont leaders disagreed publicly over Brexit. But now Mr McGuinness, who voted to stay, and Ms Foster, who was in the Leave camp, have tried to present a united front.
In their letter, they told Ms May the North was unique because of its land Border with the Republic. They wrote about protecting jobs and the economy and referred to how the Border must not become “a catalyst for illegal activity or compromise in any way the arrangements relating to criminal justice and tackling organised crime.
“It is equally important that the Border does not create an incentive for those who wish to undermine the peace process and/or the political settlement,” they added.