Before she was a novelist, Fay Weldon worked in advertising. It was she who gave us the famous slogan "Go to work on an egg". Plugging things, then, must be in her blood - which is doubtless why she paused for only a second when the Italian jeweller Bulgari asked her to write a book that would include at least a dozen mentions of its baubles. Having banked the cash, Weldon set about the task with gusto. The Bulgari Connection - a novel that unashamedly takes product placement to new heights - is the result.
Weldon used to write rather good little books, peppered with naughty sex and racy feminist politics. Then, overnight - or so it felt - she went all girlishly iconoclastic on us. Women, she said, should not be so hateful to their menfolk; those in therapy should get up off their couches and walk. And now this: a batty, breathless fable about money, celebrity and vulgar-sounding gold necklaces.
Barley Salt is a rich, middle-aged businessman with a fat chauffeur, a regular table at the Ivy and a vast pile in the country. He has left his wife of many years, Grace, for a much younger woman called Doris Dubois. Wife number two is the presenter of a BBC arts programme and a girl about town - sort of Joan Bakewell meets Anthea Turner. She is also a grasping minx who wants Barley only for his money. At a charity auction, she sees Lady Juliet Random, an old friend of Grace's, wearing a valuable and distractingly unobtainable one-off necklace by you know which jeweller. She wants one too, thank you very much.
The discarded Grace, meanwhile, is spent and confused. She has already tried to run Doris over in her car, and has served a prison sentence as a consequence. Her parole agreement means that she must see a suspect shrink called Dr Jamie Doom. She has a gay son, Carmichael, a dress designer, but he is far away in the Antipodes. The friends she and Barley shared before their divorce are kind - but only up to a point. They invite her to lunch, but not to dinner. Single women do so ruin a seating plan. She is lonely. Life is not good.
What next? This being Weldon, a reversal of fortune is in order. Grace meets a young painter, Walter Wells, and they fall in love. Her looks - and her waist - return as if by magic. Doris, meanwhile, gets into all sorts of trouble, and the hard little flint that is her heart is revealed to her colleagues, her acquaintances (she doesn't have friends) and, finally, her husband, Barley. In a desperate bid to ruin Grace's life further, Doris flirtatiously asks Walter to paint her portrait. In it, she will be wearing a necklace just like Lady Juliet's (that'll teach her). Perhaps you can imagine what happens to her face when, on the occasion of the portrait's unveiling, a film crew aims its hot arc lights at the canvas.
Weldon's world gets spookier and more primitive in each novel she writes. Her writing inhabits a bizarre parallel universe in which women menstruate during a full moon and oral sex is good for the complexion. Wifely goodness is rewarded; restless ambition is not.
Weldon's long-standing habit of writing in short bursts - her paragraphs dotted across the page - is starting to seem distinctly feeble, as though she were some consumptive 19th-century creature with barely the energy to pick up her pen. Please, someone, pass her the smelling salts.
Then there are the endless mentions of Bulgari. These jangle loudly on the page like a particularly chunky charm bracelet. But Weldon's agent has already announced how delighted he is that his author has opened the door to companies who might want to sponsor literature in the future. The sky, he says, is the limit. I am convinced he is wrong. What this story really lacks is sparkle.