Only two debates, both on educational policy rather than politics or finance, generated the heat customarily associated with a teacher union conference when the Scottish Secondary Teachers’ Association met in Dunblane. The divisive issues were classroom indiscipline and the more arcane matter of reporting individual elements in Standard grade assessment.

Delegates, representing 7,000 members, concurred on all other matters, attacking underfunding of secondary schools, the waste of local government reform and the direction of Labour’s proposals for Scottish education.

The most controversial motion, calling for legislation to exclude trouble-makers from the classroom, was referred to the union’s ad hoc committee on indiscipline.

Joe McKelvie, Angus, the association’s national treasurer, said indiscipline was “growing in size, seriousness and complexity” and would not be tolerated in any other workplace. Every child had a right to be educated but children who abused teachers did not have the right to be educated in mainstream classrooms to the detriment of teachers and other pupils.

Mr McKelvie said: “According to some of my young charges, I am a horse’s hoof, a Chicago banker and of very doubtful parentage. I have been shown one finger, two fingers and even a whole arm. Nothing too serious in any of these, but if I were to act in a like manner, I would be banned from my local pub, asked to leave the bowling club, refused service in a restaurant or arrested for breach of the peace and ostracised by my colleagues.”

Teachers were often accused of failing to understand individual needs but for repeated acts of abuse there was no option except exclusion. “Every murderer, rapist, wife beater, child abuser, violent robber, mugger, road rage raiser passed through the school at some stage,” Mr McKelvie said.

“Perhaps if some of our fears were recognised and acted upon earlier with appropriate action then, just maybe, some unhappiness, some pain and some tragedy might be averted in the future.”

But John Gray, Aberdeen, a past president, said the motion was “a counsel of despair” on the “most fundamental” issue facing the conference. He did not support the notion of permanent exclusion, nor a policy based on anecdotal evidence. “We would be doing nothing for those who will be excluded,” Mr Gray said.

Peter Wright, West Lothian, said the issue involved “a crisis of conscience” for teachers. He had been assaulted by a pupil many years ago and recently came close to being assaulted by a parent but he was strongly opposed to exclusion.

Mr Wright was supported by Andy McAuley, Glasgow, who said the motion was “outrageous”. Teachers would be prosecutor, jury and judge.

In a related motion, Michael O’Kane, Fife, said that indiscipline was “destroying the heart and soul” of schools and must be tackled by the Government. During the past year he had twice been threatened with serious physical violence.

“Twice I reported the young people to the police and twice they told me that since their own powers are limited, there are few legal avenues they might follow,” Mr O’Kane said. “As a result, the young people were either warned or charged but nothing else was or could be done.”

Ministers’ “blinkered attitude” meant that seriously disruptive pupils remained in the mainstream, spreading a “malicious influence” and preventing other pupils from learning. Pressure was needed to compel social work departments, children’s panels, attendance subcommittees and sheriff courts to take responsibility.

Alan Lamont, general secretary, said earlier that further delay by the Scottish Office over tackling indiscipline was “wholly unacceptable”. The unions had met with the Raymond Robertson, the Education Minister, on February 7 and were promised immediate action.

“We have not heard a dickie bird since,” Mr Lamont said.