Even when it comes late in life, after the rest of the family has grown up and gone away, you cannot fail to feel a flush of pleasure and hope.

But when the child shows little inclination to speak and seems unable to grasp the rudiments of walking, when your fears slowly and horribly mount, the awful truth must be faced and hope crashes to tragedy and pain.

So with Barbara and Peter and their late-born son Tim. This is the brilliant story of the agony that enters their settled life: the obsessiveness, the dangerous selfless love, the heart-wrenching contradictions, and the violence - both mental and physical.