LONDON (AP) — Northern Ireland's top civil servant is warning that a disorderly U.K. exit from the European Union will lead to a sharp increase in unemployment and an exodus of businesses from the region.

David Sterling says "there is currently no mitigation available for the severe consequences of a no-deal outcome."

Britain and the EU have struck a divorce deal, but the U.K. Parliament has rejected it, largely over concerns about the Ireland-Northern Ireland border.

Britain is due to leave the EU on March 29, and businesses fear a "no-deal" exit would severely disrupt trade. It could also destabilize Northern Ireland's peace process, which relies on an open border.

In a letter to Northern Ireland political leaders, Sterling says a "no-deal" Brexit "could well have a profound and long-lasting impact on society."