"Business people stuck the knife in over the fuel crisis. It was the trade unions that backed Mr Blair," said Nigel de Gruchy, general secretary of the National Association of Schoolmasters Union of Women Teachers.
Most teachers voted Labour last time and the Prime Minister will need to take as much note of their backlash against his education policies as he will of his mauling over petrol.
Initiative overload, bureacracy, low pay, performance management and the pressures of inspections are contributing to falling morale and a recruitment crisis.
The unions will be putting Education Secretary David Blunkett on the spot over recruitment, standards and the future development of the profession at two key fringe meetings.
"Labour inherited a deeply disillusioned teaching service," said Pete Smith, general secretary of the Association of Teachers and Lecturers. "The question teachers will ask at the next election is - have they made it worse or better? If anything, I feel they have aggravated the mood."
Mr Blair will no doubt have a few words to say about education in his keynote speech on Tuesday. But headteachers are still "incandescent" about his claim earlier this month that comprehensives needed modernising, and should do as well by the brightest pupils as grammars.
Some Labour delegates also have concerns on the issue. Charlotte Atkins, a member of the Commons Education Select Committee, said comprehensives were "very much at the forefront of good education practice".
But modernising and promoting comprehensives remains one of four key elements of Labour's programme for schools, according to a party national policy document that provides the basis for the education debate on Wednesday. That will be Mr Blunkett's big opportunity to shine.