‘If we were forced to live by our own efforts, how’d we thrive? It stands to reason we couldn’t do it. Our senses are blunted. We depend on a multitude of people to make our clothes and food and tools for us. We have noses that can’t smell, ears that are deaf …’

Hugh, on the other hand, sees man’s intelligence as the factor which would enable him to survive and feels sure that if driven to it man would find within himself qualities and potentialities he has long since forgotten. In taking himself and his wife into the wilderness he has to discover these qualities to keep them alive. Intelligence, he quickly realises, is not just the theorising intellect. It is not that kind of intelligence that sustains them so long, but a combination of mental and physical agility and resilience.

Macpherson himself makes no attempt in the book to argue a case for pacifism. He is much more concerned to involve his reader imaginatively in the plight of his two central characters through the device of the journal, and to highlight the futility of war by showing how valuable are the things it destroys. In the face of a war which threatens to engulf the world, Hugh and Terry desperately try to preserve their love for each other, and on that level their story must be emblematic of all those other human bonds and relationships broken apart by wars since the beginning of time. The reader is constantly made aware of their vulnerability. At times they are described clinging to each other like children lost in a threatening world they do not understand. At times they are seen as anxious, frightened figures against a background of disturbing apocalyptic imagery: ‘the future had no light; we lived on the edge of a world gone mad’. As their isolation from the rest of the world deepens and their nerves begin to crack under the strain of it all they begin to argue with each other. Whatever their faults, perhaps because of their faults, the reader is moved to care about these characters because in them is revealed much of our own human frailty and vulnerability.

We respond, too, to the desire to find a secret place where we can be safe from the pressures of the outside world which even in peacetime can sometimes threaten to overwhelm us. On a simple level the game of building a den where we can feel secure and in control is something we have all done as children. For Hugh and Terry it is no game: it is quite simply a matter of life or death.