The NAHT general secretary had warned that withdrawing from the agreement would “achieve absolutely nothing” but delegates decided to ignore the advice of a leader they would once have followed through the thickest bramble bush. Nevertheless, the vote came as no surprise. The NAHT has consistently warned that it would pull out of the deal unless there was “clear, adequate and direct” funding for the reforms. That has not been provided. The workforce agreement has undoubtedly produced substantial gains for teachers. No fewer than 24 administrative tasks have been passed over to support staff and the number of hours a teacher can cover for colleagues each year has been capped at 38.

But hundreds of schools are convinced they do not have enough funding for the planning, preparation and assessment time that teachers must be given from September. And their anger has been palpable. As one Preston head said in a letter to The TES: “In 22 years of headship I have never known an issue which so exercises, worries, angers and demoralises headteachers.”

It is too early to tell precisely what the implications of Wednesday’s vote will be. But it is clear who the main losers are: the NAHT leadership and the Government, which can hardly continue to boast of a concordat with the teaching unions if both the National Union of Teachers and the NAHT have walked away from the deal.

Wednesday’s vote will also be a deep disappointment for David Hawker, the official candidate for the post vacated by the soon-to-retire Mr Hart. As a committed supporter of the agreement he said he would have to reconsider his position if Wednesday’s vote went against the NAHT leadership. So even if he wins his head-to-head contest with his rival Mick Brookes he may decide he does not want the job anyway.

The NAHT has never known such interesting times.