The resignation of Brandon Lewis, the Northern Ireland secretary, presents "yet another complexity to the educational landscape in Northern Ireland", a school leader has said.
Dr Graham Gault, interim director of school leaders' union, NAHT(NI), said: "Without a devolved government in Belfast or a Secretary of State to Northern Ireland in Westminster, it is unclear who we can even appeal to in relation to the extensive industrial challenges that are intensifying.
"On behalf of school leaders, therefore, I appeal to those politicians who are hindering the formation of the Northern Ireland institutions to search for ways to set aside strategic positions in order to reestablish governance here to allow us to make some progress.
"The industrial temperature across all public services is at a critical state. You must be under no misapprehension that NAHT(NI) is one of many trade unions that will be taking decisive steps to protect our members on the other side of the summer."