Events at Dunblane primary have again brought school security to the fore. Most commentators agree this sort of crime is the most difficult to prevent without turning schools into high-tech fortresses.

Fred Forrester, depute general secretary of the Educational Institute of Scotland, warned against knee-jerk reactions and said: “It is inconceivable how such an incident could be prevented.”

The last time a fatal shooting occurred in a Scottish school was in 1967 when a man burst into St John’s High in Dundee and shot a woman teacher. The scale of the shooting has only been matched in recent times by the massacre of 16 people in Hungerford in 1987 by Michael Ryan, who also turned his gun on himself.

Union leaders called for a review of security in schools. Ronnie Smith, general secretary of the EIS, said: “Schools are supposed to have strong links with the community and to be places where parents are welcomed. But we obviously have to think carefully about measures that can be taken.”

Peter Smith, general secretary of the Association of Teachers and Lecturers, called for a review of penalties for carrying unauthorised firearms and a clampdown on unauthorised entry to school grounds.

Robin Squire, the schools minister in England, is due to publish a report on security at the end of this month. This was commissioned following the death of Philip Lawrence, the London headteacher stabbed outside his school in December as he defended a pupil.

The Working Group on School Security, which includes representatives from unions, governors, police, the Home Office and the Department for Education and Employment met last week to consider new legislation which will make carrying knives in schools illegal and give police new powers to enter school premises Two years ago a man gained entry to Hall Garth school, Middlesbrough, and killed 12-year-old Nicola Conroy and injured two other girls. The school is still recovering from the incident.

The layout of Dunblane primary does not make such a system appropriate even if the school could afford it. A former junior secondary, the school is spread out over the site with a number of mobile classrooms.

Ian Collie, former director of education for Central, who knows the school well, said: “It would be very difficult to install an effective security system at the school.”