It was one of the lowest moments in the EIS' recent history, as members threatened mass defections and a sizeable section of the teaching workforce felt betrayed by Scotland's largest teaching union.
Supply staff appeared to have been sacrificed for the greater good of their permanent colleagues, as the Scottish Negotiating Committee for Teachers proposed a drastic pay cut for short-term cover - as much as 50 per cent - and fellow union members voted to accept the deal.
That was back in 2011 and bitterness was rife. It has taken until this month for the union, under Larry Flanagan's leadership, to wring a better offer for supply staff out of councils in this year's national pay talks. The discussions should have been concluded in April, but they still depend on changes to working conditions that are only now being put to the ballot. But will the improved offer of a return to full pay after three days of supply - instead of the current five - plus a 10 per cent increase for preparation and marking on those three days resolve the matter?
Although the media have run numerous stories of schools being unable to find cover, and news of the negotiating "breakthrough" was widely publicised in the press, it has been met by a resounding silence. There has been little evidence of jubilation among supply staff - perhaps because so many had already voted with their feet, or perhaps because those who remain value their professional skills from Day 1 of a job and expect to be paid accordingly.
If the downgrading of supply teachers was intended for the greater good of the workforce as a whole - on the grounds that savings would help to protect jobs - it was massively shortsighted on the part of all concerned: government, local authorities and unions. At the very time when Curriculum for Excellence was being introduced and a new exam system drawn up, teachers and managers needed access to more cover, not less, to help them cope with the pressures.
When supply teachers refused to work for low pay - many moving to other careers or other shores - teachers and senior managers found themselves having to plug the gaps. One way or another, they paid the price as the false economy rebounded on everyone.
So could the new offer make a difference?
Minimally, perhaps. It's a step in the right direction, although the problem of devaluing an important section of the workforce remains. But when teachers vote over the coming days, inevitably it will be changes to their own pay and working conditions, following the McCormac report, that will be uppermost in their minds. It won't be supply staff.
Gillian Macdonald is a former editor of TESS.