Art and design teachers have drawn up a catalogue of complaints about the quality of assessment at Higher and Advanced Higher and are to petition MSPs for a review of the Scottish Qualifications Authority.
They complain that some S6 students are being accepted for art college on the strength of their folio work yet are failing Advanced Higher when they present similar efforts.
But the SQA stoutly defends its assessment processes in art and design and its system of checks and balances.
A ginger group, led by Bill Smith, principal teacher at Ellon Academy in Aberdeenshire, this week reignited the concerns of last autumn when experienced teachers challenged the SQA over its direction of post-16 courses and exams. They said that no one was listening to the classroom voice.
Meeting again in Perth this week, 21 teachers passed a vote of no confidence in the SQA after gathering together more tales of rogue results.
Mr Smith said that experienced teachers, some of whom were markers, were "incensed". He warned that it was "pretty clear there is something fundamentally wrong with assessment procedures in art and design".
All secondaries in Midlothian were appealing against their results, as were nine out of 10 in Dundee, six out of seven in Stirling, 16 out of 17 in Aberdeenshire, 20 out of 27 in Highland and nine out of 10 in Borders.
One Highland teacher described the Higher results as appalling. "There was mayhem in department predictions", particularly in design. One student who achieved 96 per cent in the expressive element went on to fail design.
A Renfrewshire teacher said: "A colleague who is a marker for the Advanced Higher has had three-quarters of his pupils fail at Advanced Higher."
But the SQA hit back hard. Mike Haggerty, its spokesman, said that appeals in Higher art were down by 25 per cent and an independent consultant had commended the quality assurance systems in the subject "in what might be considered a very subjective area for assessment".