The decision by Strathclyde Regional Council was condemned yesterday by teachers' leaders who said it would increase the risk of violence in the classroom.
The Sikh boy, who has not been named, was suspended from the Thomas Muir High School in Bishopbriggs in April after he was found carrying a ceremonial dagger, called a kirpan. Education officials wrote to his parents telling them that the 6in curved blade, which Sikhs are permitted by law to wear in public, contravened Strathclyde Region's strict ban on weapons in schools.
The parents argued that the dagger, which indicates a baptised Sikh's status, was not a weapon but a sacred religious symbol. They refused to allow their son to return to school without it.
After three months of talks with the family, Strathclyde Regional Council agreed earlier this week to allow the boy to carry the blade provided it was worn under his shirt and stored in a metal case, with the hilt tied to the sheath to prevent it from being drawn.
The decision, the first time a pupil north of the border has been given permission to carry a weapon in the classroom, has angered teaching unions. Eamon O'Kane, deputy general secretary of the National Association of Schoolmasters Union of Women Teachers, which represents 140,000 teachers, said it set a bad precedent. 'Clearly, it is a difficult situation when you are dealing with cultural and religious matters. But the council should have stood firm. The authority should have told the parents: 'The rules may seem unfair to you, but we are not prepared to tolerate offensive weapons in schools'.'
The decision could legitimise the carrying of knives, he added. 'How many more families living in Glasgow and other cities will now demand that their sons be given the same right?
'And then you have to consider the effect on the atmosphere in the school. The other pupils will know that this boy has a knife and they may feel that they are therefore entitled to carry one too, for so-called self-defence. It could create a dangerous spiral,' he said.
With reports of attacks in schools rising - a 16-year-old girl died recently after she was stabbed at Whitehill School in the Dennistoun area of Glasgow - the decision would not, he added, act as a deterrent. But David Alexander, deputy director of education in Strathclyde, said that the decision was an 'amicable agreement' between the council and the Sikh community which would not encourage violence. 'We are very conscious of the need for safety in the classroom. Similar arrangements exist in Bradford for the carrying of the kirpan in schools and there is no evidence that it causes problems.
'The two big issues were whether the kirpan could be seen and whether it could be drawn. The conditions we have imposed are very strict and they mean that actually using the knife would be extremely difficult. Moreover, the Sikh community is adamant that the kirpan is a sacred symbol, and not for practical use.'
Mr Alexander added: 'Very few Sikhs in Scotland have been baptised so we are not talking about setting a precedent for thousands of people.'
The deputy head teacher at Thomas Muir High School yesterday declined to comment.