David Walker, a retired headteacher and now an Office for Standards in Education inspector who only took over as national chairman on Tuesday, made his resignation statement to the 200 delegates at the PAT's annual conference in Derby on Wednesday after a radio interview in which he "inadvertently expressed views which are quite outside PAT policy".
Claiming he had been pushed to go beyond an earlier statement on class size, Mr Walker said: "The job of any national chairman is to uphold policies of the association and to express the views of members - your views . . . I have no alternative but to resign - and have done so because of my respect and affection for the association and the harm which my ill-considered comments could do."
Mr Walker's speech, scheduled for Tuesday evening, was released last Friday and reported in some of the weekend's papers, leading him to make a statement at the start of the conference clarifying his remarks. "Our objective is . . . professional flexibility within a controlled framework. PAT's evidence to the School Teachers Review Body on pay said that no teacher should teach in a class of more than 30 unless the staff agreed it was reasonably desirable."
But he appeared to reverse this in a BBC Radio 4 interview on Tuesday evening. John Andrews, general secretary of the 40,000-member association, which celebrates its 25th anniversary this year, said there had been a "strong reaction from members".
In his original speech Mr Walker said the issue was complex: smaller classes did not automatically mean better teaching and learning. Some subjects, such as reading, needed small classes. A group of 40 well-behaved children could be quite manageable. "But we've all known the other kind, haven't we? Those that make a class of a dozen a nightmare . . . Given these variables, it is a nonsense to place an arbitrary number on the size of a class."
When asked if Mr Walker had been told to resign, Mr Andrews said: "We actually hardly had to say anything at all. He knew what he had to do." Mr Walker, who was visibly upset after giving his statement, left the conference via a fire exit with his wife Christine.