Glenda White, an education consultant and latterly a South Lanarkshire senior official, told headteachers in the capital on Tuesday she now had the freedom to speak out.
In a sweeping broadside, Ms White slammed a constant denigration of schools, target-setting, the 5-14 programme and the externally imposed, initiative-driven agenda that for more than a decade had demoralised teachers.
Workload was up, morale was sapped and too much attention had been drawn from teaching and learning in the classroom. Competent and creative staff had been forced into an "endemic culture of guilt" by repeated demands on them, including criticism from HMI and the press.
In a telling statement, backed earlier by Professor John MacBeath of the Quality in Education Centre at Strathclyde University, she said: "We need to do less, better." Expectations on teachers had been raised to unrealistic levels, particularly in the 5-14 programme where the system should have the confidence to recognise difficulties.
"Teachers cannot be expected to have the skills and knowledge to teach 22 different subjects. They have to acknowledge they are not very good at some things," she said. They spent so much time writing forward plans they had no time left to consider how they were going to teach lessons in class.
Professor MacBeath also said "something has to give" in the curriculum and believed ministers south of the border were looking more favourably on a slimmed down curriculum. "Unfortunately, if we are going o start cutting we have to be careful we do not follow some 300 English primary schools which cut out music," he said.
Ms White appealed for reasonable practice across the school involving "competent" teachers in a 35-hour week and less focus on special initiatives, which were invariably introduced using the most motivated and ambitious staff.
"We need to focus on competent teachers and responsive children. I think we spend too much time focusing on target-setting, attainment and examination results, instead of the quality of what is happening in the classroom.
"We cannot raise attainment from setting targets, only by the quality of teaching and learning in the classroom."
Ms White, who has spent most of her career in quality assurance, added:
"Quality initiatives are not going to be sustainable if they are imposed externally, specially funded or staffed, increase workload and detract from teaching and learning."
She warned that Scottish education would lose its best young people to other professions unless issues of workload and teacher expectation were tackled.
Ms White called for a refocusing on teachers and the classroom where there was already much excellent practice. Teachers were extremely well qualified, skilled and experienced and had to be trusted to deliver while staff had to feel more valued.
She recommended a campaign to promote the positive role of the profession. "It's not good for society if it does not have confidence in its teachers," Ms White stated.
She urged headteachers to celebrate achievements wherever they could and recognise schools were happier places to learn than they had ever been.