Enhanced security in schools, with police officers? Please walk through the metal detecting arch, Sir? I suppose it would be possible to turn all schools into fortresses with coded access control, or with iris recognition technology. And yet surely this is not how schools were supposed to be?

I did my teaching practice many years ago in a highly prestigious school in the middle of a run-down ghetto in one of our major cities. They would lock the gates every day to keep out the villains. It was the price they were prepared to pay for their privileges. But because of that, the school never fitted in. It was a different land to which the community had rare access. I thought we had moved on from all that.

Our obsession with security will have a huge impact on our pupils. What sort of message are we giving children if we conduct education in such circumstances? What lesson will they actually learn? We will tell them that learning is a threat and a danger.

Scan kids for weapons and what will happen? It will be a fantastic challenge to any oaf in Year 10. Their one abiding mission will be to smuggle a knife into school - not to use, but to prove it can be done. Once we start along this path where will it end? What message is now the school’s priority?

Most of our schools were designed at a different time, with different priorities. Suddenly containment and security are everything. We have any number of exits in my school. The caretaker tells me there are 36. Each one is also an entrance, making the building almost impossible to manage.

In this climate the teachers develop a sense of threat, because anyone can get in if they choose to do so, especially ex-pupils. Usually they turn up to tell you how they are doing and it is good to see them. But if they really do have a grudge, then they know exactly where to go to track down the person they are after. They know exactly how to bypass any security procedures you have in place. Then it is up to teachers to manage it, as they always have done.

My main concern is the effect of this security obsession upon the generation of children going through our schools with locks on doors, entrance management and security guards. They will be safe from unreal threats and we will be able to measure our success in a lack of incidents.

What we are dealing with here is something indefinable, which of course is an unpopular idea these days, for everything needs to be measured. But atmosphere and anxiety cannot be quantified, no matter whether it is real or imaginary. Learning cannot prosper when surrounded by fear.

Learning made free and accessible - that is what we have always believed. It shouldn’t take place behind barriers.

Of course many schools were built at a different time when we were not so agitated about child safety. Now everyone is a threat. There is nothing that speaks of the different priorities of the generations more than this.

The future we are living - full of anxiety and threat - is not the one that was planned for us. And a sense of paranoia has absolutely no place at all in school. They are about opening up and stretching horizons. Schools will never prosper if they are inward-looking and frightened.

Geoff Brookes is deputy head of Cefn Hengoed School in Swansea.