We have had a new fence installed in our back garden. It consists of seven 1.5-metre-high panels that have been pressure treated against rot and fungal decay. Subject to a number of maintenance conditions, it is guaranteed to last 15 years. And because Mrs Eddison insisted on it being aesthetically pleasing it came with an elegant trellis, flowing lines and an eye-watering price tag.

But its primary function is not to enhance our garden, it is to prevent Scruffy running away to the big wide world beyond. He arrived at our house last spring, having come all the way from the mean streets of Cyprus via a dog rescue centre in Doncaster. It was a journey that appears to have inspired in him a wanderlust that our former, badly neglected, lattice fence could not contain.

Gardening is primarily Mrs Eddison’s area of expertise. Thanks to her zealous application of weed and feed over several years, our grass is much greener than the man’s next door. What attracts Scruffy to his garden is the absence of a gate at the end of it. Now, with his best means of escape cut off, his only option is to cock his leg against a rot-resistant cedar fence post in frustration.

But what Scruffy doesn’t know is that our new fence is there for his own protection. He has no idea that the big wide world beyond is fraught with dangers. Men who come from out of town and steal small dogs to train their pitbulls to kill. Cuddles, the psychopathic bull-mastiff who lives just across the road. The vicious pack of Airedales at number 32. And scariest of all, the semi-feral ginger moggy (aka Resident Evil), who resides where he damn well pleases.

Harrison has a lot in common with Scruffy. He is largely dishevelled. He comes to school against his will. He retains a desire to roam the big wide world beyond. And he has no sense of danger. He doesn’t understand that our anti-climb V mesh fencing system is there because we love him. Like Scruffy, he inspects it for signs of weakness (although, to the best of my knowledge, he has yet to urinate on it).

Since safeguarding became the number-one school priority, new security systems have proliferated. Escape-proof fences, electronic gates, surveillance cameras and door locks controlled by intercoms have been installed. But there are two sides to every barrier. Fencing children in may keep them safe, but doesn’t it also make them prisoners? And isn’t our obsession with educational barriers (policies aimed at sanitising school trips, insulating outdoor learning and restricting children to a straight and narrow curriculum) a reflection of our need to reduce risk to the point of tedium?

Last night, Scruffy heard the call of the wild and woke us with a volley of frantic barks. From our bedroom window I caught a glimpse of Resident Evil, standing by our upturned wheelie bin with a chicken carcass in his mouth. He posed in the white glare of the security light long enough to make a point and then was gone. Over the fence and into the big wide world beyond.

Steve Eddison teaches at Arbourthorne Community Primary School in Sheffield