I’ve gone off Mary Wesley since she started a book with a string quartet playing Bach (unlikely) with a conductor (impossible); Trollope handled music better in The Choir, so now let’s see what Jilly Cooper does with this Appassionata, which is set in the world of classical music. First, a dedication to the Royal Scottish National Orchestra and a foreword in which she thanks by name upwards of 140 performers for their time, experiences, stories and comments on the musical scene.

Having been a part of that scene myself for half a century, I know it well and, indeed, many of the stories, especially the ones that take the mick out of conductors – orchestral players can really be master baiters of those who lead baton charges. (Incidentally, Jilly Cooper says that her current dogs are called Rattle and Tilson Thomas.) After the foreword we still don’t begin the novel because there follows a cast list of characters, 117 of them, with a few words of description about each of them, which is helpful since the convoluted novel is 639 pages long. There is even a list of the dozen animals that figure in the book, including a fat black cat called John Drummond (more interested in mice than in the Proms, however). The tale itself begins off-music with Taggie and Rupert Campbell-Black in Bogota trying to spring a baby from an orphanage. Rupert is an ex-world showjumping champion (see a previous Jilly Cooper, I gather), stinking rich, Mecca for most women, bronzed and yellow-haired (Mr Heseltine?), who behaves with brutal arrogance, especially towards his pianist son Marcus, who has tendencies towards asthma and a Russian ballerino.

Enter Abigail Rosen in the title role, Appassionata, known as Abby, a young, luscious, world-famous American violinist who, after a tiff with her agent, slashes a wrist and turns conductor. But not before we have been introduced to another conductor, Rinnaldini, as brilliant as Toscanini but as wicked as he is improbable. Cooper then shifts the reader over to England, where Abby becomes conductor of provincial orchestra after proving her worth on the strength of her debut conducting, wait for it, Richard Strauss’s Ein Heldenleben (a cracker of a work to conduct even tor a veteran). Those 140 advisers notwithstanding, Cooper has Abby explaining the story of this well-known piece to the orchestra before rehearsing, which is emphatically suicidal behaviour with any orchestra: after a lengthy explanation some horn player is sure to ask ‘Do you want it loud or soft?’ At one point in rehearsal Abby gets warm and by mistake takes off not only her sweater but her only undergarment. A likely story, but it might make a useful tip to Jane Glover.

Cooper gets her music right (unlike Wesley), although a girl being bonked on top of a glockenspiel sounds both painful and impractical (a celesta is more possible). But certain situations jar: Runnaldini spends a morning showing his latest lady round Prague, even though he has to conduct the Missa Solemnis in Berlin that same evening – wot, no rehearsal for a choral piece! – and there are TV relays of orchestral concerts without any camera rehearsals. I know this is soap, but even so…l mentioned bonks, but there aren’t many and they aren’t at all erotic. Occasionally Cooper uses her new musical expertise, as when she describes Rinnaldini with ‘his splendid cock raised tor the downbeat’. Some of the musical jokes go off at demi-tumescence. Quite funny is the girl so refined that she eats bananas sideways, but it would be funnier if Cooper pointed up the fact that she is a flute player, a traverso, geddit?

The plot becomes difficult to follow because Cooper keeps moving the goalposts when it suits her. Like George Hungerford, who supports the orchestra (at times) but is also a wicked property developer (at other times) trying to ruin the orchestra and merge it, unlikely enough, with a rival authentic-instrument band. Likewise, the funding of the orchestra is pulled this way and that so elastically that the plot twangs back in the reader’s face.

The climax of the book is an international piano competition with bribed judges and skulduggery with the piano pedals, and Cooper labours what a prize it is for the orchestra to get the job of accompanying the finals – but ask any player how he likes an evening playing the same concerto three times on the trot with as many pianists.

Cooper sprinkles her novel with a few sensible homilies about the music scene, and some classy quotes: there is a touching episode between the pianist Marcus and his Russky ballerino when quotations from the text of Peter and the Wolf help them on their way to the sack. But it is not the easy read you might hope for, because of those moving goalposts in the plot and the rather jerky style; you get the feeling that many things happen just because Jilly Cooper wants to make a joke or a pun, or to show off her new-found knowledge. I got bored in the middle, but then, dammit, I rather miss it now I’ve finished it.