Ian Valentine, headteacher of Cleveden High, Glasgow, said inspectors in the audit unit were overenthusiastic about Government policy and had become detached from their school origins. They were the new "Securitate", a label attached to the former Strathclyde Region's inspectors.
Mr Valentine, addressing the association's spring conference in Perth on Tuesday, criticised the relentless drive to ratchet up "best practice" and standards at great cost to teachers. Teaching in the third and fourth years of secondary school was "incomparably" better than in 1979 but workload and stress on teachers had increased enormously.
"There is a feeling in the most able, well intentioned and most dedicated teachers that however hard they try they are never going to be good enough, " he said.
The Inspectorate had sacrificed its professional integrity in backing compulsory national testing in the 5-14 programme, ensuring that its principles "are going down the Suwannee". He said: "Not the least of the sad aspects of this is that when garbage like national testing 5-14 comes out, a lot of well-meaning professional people begin to see it reluctantly as the only possible way forwards."
Mr Valentine admitted that publishing tables of examination results had caused headteachers to re-examine their practices and seek to improve levels of attainment. But in the Glasgow context they did not tell the full picture. "I maintain that in this scene of deprivation and often a scene of despair, if we can get our weans to keep on coming, keep on trying, finish their four years of education and get a certificate, then we have achieved hugely. The trouble with the league tables is that little recognition is given to that," he said.
Other statistics published by the audit unit, including attendance figures, school costs and leaver destinations, were a waste of time but continued to be highlighted in the media. "I felt like putting out a press release saying 'We may not be good, but we're cheap'," he told heads.
Turning to the latest series of Scottish Office reports, Mr Valentine said Achievement for All, which backs setting, was "full of unsubstantiated, homely Sunday Post-type sayings" which would mean "achievement for some at the expense of the rest".
Children who were not naturally well motivated and who struggled learnt better with role models. Setting meant streaming.