Well, Sarah felt very peculiar indeed. Nauseous, alternately hot and cold, sore breasts. Was this the dreaded menopause? Was she entering into the sere of life at last? Her feet felt heavy, as though her boots were clogged with mud, and her eyes could not tell whether the traffic-lights had changed. She had better visit the doctor’s surgery. A heavy fog had settled like a foreboding, and as the walls of the building loomed up before her, her heart started to beat faster. She hesitated on the threshold, fearful of what she might discover.

The doctor conducted various tests and told her that she was pregnant. Feeling dizzy with shock, she needed some fresh air, and stood by the open door for a moment, although there was now nowhere to run to. How could this be? She had no partner, had had no gentlemen callers or assignations. How could this be?

The baby grew inside her apace, and the birth was surprisingly easy. One minute Sarah was alone, and the next minute she was not. She called the baby Sally. And indeed Sally turned out to be a miniature version of herself, identical in physical type and in temperament. But as she grew, something very odd started to happen. Sally seemed to have silently intuited certain problems Sarah had had in her life, and was clearly intent on avoiding them. When a child, Sarah had found it very difficult to ride a bike, and had fallen off many times: her knees had been a perfect record of her clumsiness. When Sally was given her first bike, she fell off just once, and then stopped and looked at the bike hard, measured the length of her legs, adjusted the height of the seat, and then sped off down the road. It was the same with horse-riding. Sarah had been thrown off many times: and when she bought Sally a series of lessons, the child stood stock-still and gazed into the pony’s eyes. She mastered him at once, and he did her bidding at a fast trot.

And that was not all. Sally remembered everything Sarah had read. She started to tell her about Jane Eyre, and after recounting the scene in the Red Room, the child remarked: “Mummy, is there a madwoman hidden in every house?” Sally knew the Norse myths before reading the book her mother had treasured for years, and she somehow knew by heart the long Victorian novels Sarah had read. As Sally grew and was taken to the cinema, it was embarrassing when she shouted out the denouement of the films: “don’t go into the shower!”, “Rosebud was his sleigh!”

So far so good. This could all be quite amusing, and at least her daughter had saved herself an awful lot of time by unconsciously internalising everything her mother had read or seen. It was imbibed through the blood and gall: through the bones and fascia, perhaps. Sarah didn’t feel threatened by it at first: it just meant that Sally was not like other daughters. What really troubled her was when Sally got older: she seemed to be learning from Sarah’s emotional mistakes, even though she had never been told what they were.

Sarah had always been too accommodating and eager to please: “O yes, I can do that!” was her constant refrain. As she grew up, Sally never ever said that: she thought long and hard before acceding to any request. Sarah struggled with her weight: Sally had a little pen-knife in her bag, cut any treat in half, and just ate that. Sarah’s love-life had been catastrophic, and it often seemed that she had sought out the most unsuitable man in the room and then recruited him into her service. Sally was more considered. She didn’t exactly ask for references from prospective lovers, but she never ever ran into bed with them, as Sarah had done. Amorous regret seemed foreign to her.

Sarah began to have mixed feelings about her daughter. Sally seemed a living reproof. They watched each other, circled each other like gladiators. Perhaps, after all, there was a kind of reincarnation going on? The daughter was an improved version of the mother, maybe, and the rows of eggs hidden inside her could stretch out to the end of time. But to the end of Sarah too, of course, She began to notice that she was getting fainter, and more blurred round the edges: she felt etiolated, like a plant that had been kept in a cupboard. Something must be done.

She decided to play a more active part in her own life. She too bought a little pen-knife, and used it judiciously. She too started to think before she spoke. She experimented with putting up a sort of screen in her mind, so that when she read anything or saw anything, Sally could not get at it. Had Sarah been too porous somehow, so that Sally had found everything out by a sort of osmosis? In any case, it must stop.

Then something unexpected happened. Sally started making mistakes. She bought an unflattering beige cardigan, and one of the buttons came off at once. She went to bed with the father of one of her friends, and it ended very badly indeed, with her hiding in a wardrobe and him stealing her underwear. She lost her temper with an important client. She ate a whole Christmas cake.

Of course, Sarah felt ambivalent about all this. On the one hand, she felt sorry for her daughter, who was not used to embarrassment and personal failure. On the other hand, it served her right for having been smug for so long. At least things were more balanced between the two of them now. But it still felt savage: watchful antagonists round a flickering fire. It was a sort of dynamic tension, in which they were each in thrall to a dangerous equal. Not like normal family life at all.