King Charles III and Prime Minister Liz Truss now lead a United Kingdom with profound divisions.
However, when this ends with the late queen's funeral Monday, the new heads of state and government, King Charles III and Liz Truss, will be left leading a United Kingdom that is profoundly divided.
However, the EU, the Irish government and most nationalists in Northern Ireland oppose any unilateral changes to the treaty.
Nationalists, who are growing in numbers in Northern Ireland, Scotland and Wales, might see this as the moment to unravel the union.
Peter McLoughlin is a lecturer at Queen's University Belfast, where he focuses on contemporary political history in Ireland and Northern Ireland.