Teachers on the brink of collapse due to stress are well documented in the media. Their fictional counterpart in this darkly comic novel, Caleb Duck, has already toppled over the edge, but is still in post as head of “integrated studies” at a tough comprehensive.

Caleb operates in a drug-induced haze, seeing enemy salvoes within every memo from the hated deputy head and indulging his fantasies of violence and retribution. The burden of teaching pupils with a vast array of academic and emotional problems has filled him with “pent-up poisons” and his response is to manage his charges in the spirit of a feudal baron. In return for listening to his increasingly bizarre commands, and tolerating his maniacal behaviour, he lets students run protection rackets and peddle pills. One of them, Errol, is not only allowed to spend his nights in the department, but given the job of night watchman.

Caleb cannot accept his own fragile state of mind (increasingly more fragile as an Ofsted inspection looms) and refuses to seek help for his paranoid delusions. His war with the deputy is conducted in his own mind as well as face to face. His assemblies feature rabble-rousing testimonies, and culminate in full-scale raves. It seems that his only escape can be found in running around a field with a cow balanced on his bck, and in obsessive home improvements. His domestic situation is no oasis of calm, as his wife has wisely chosen to leave him and Caleb adds stalking to his extra-curricular activities.

Allen is a former teacher. He is often crisply funny in the style of Tom Sharpe and has created a smattering of excellent characters such as Errol. The missives, forms and questionnaires which appear throughout the book add a touch of authenticity, and there are some majestic scenes such as the one in which the inspectors arrive to find “garlands of flowers placed around their necks by scantily dressed maidens”.

Although the tone is surreal, it is clear that events in the book are rooted in real crises in schools. Allen’s concluding recommendation in the fictional “Bradley Report” that teachers who work with children with emotional and behavioural difficulties should be “entitled to one year’s sabbatical after each three-year period” makes perfect sense.

If you need an uplifting read to relieve the pressure of the job, then this tale should come with a health warning: it will not make your outlook any brighter. If, however, you’re in the mood for a journey inside the warped mind of a burnt-out teacher-soldier, and enjoy acerbic humour and caustic observation, then this comes highly recommended.

Jonny Zucker teaches at West Acton primary school, London