Witches: A Tale of Sorcery, Scandal and Seduction, by Tracy Borman. Jonathan Cape, £20

In the cold spring of 1618, young accused witch Philippa Flower confessed to having “a Spirit sucking on her in the form of a white Rat”, who promised to make Thomas Simpson fall in love with her “if she would suffice it to suck her”. This frankly weird-seeming announcement was enough to ensure her conviction and execution for witchcraft, and also to implicate her sister and her mother. The Flower women were charged with bewitching the children of the earl of Rutland, killing one of them. Tracy Borman tells this strange, compelling and ultimately inconclusive story in Witches.

Borman is eager to find out what lies behind the Flowers’s story. What really interests her is the involvement of the earl and his family, and the book doesn’t really come to life until George Villiers, Duke of Buckingham, lounges elegantly into it. Retold with verve in the second half, the Flower case is about nobles and inheritance, not about weird pets. The Rutland/Manners family, Borman thinks, were the targets of Buckingham’s chilling ambition. He had decided to marry the young and apparently mentally deficient Katherine Manners, so it was a bit too convenient that the earl of Rutland’s other heirs died of “witchcraft”; a cover, Borman surmises, for a poison brewed by Buckingham’s own wizard, Dr John Lambe.

Like others before her, Borman is frustrated by the difficulty in imagining the lives of the Flower women or the thoughts that filled their minds. She sometimes tries to fill the maddening gaps with sensational language, racing for irrelevant torture descriptions, and overwriting and overstating at every turn. Seeking added colour, Borman cites Continental cases and especially tortures and punishments as if the issues involved are the same as in English trials.

Appalled by the irrationality of witch beliefs, she is only willing to attribute those beliefs to the people outside her story. For her, Buckingham is a chilly Machiavelli, and the Flower women the dupes of crazed patriarchs. The trouble with this black-and-white appraisal – bad witchhunters, silly witches, cold-hearted courtiers - is that it risks not taking us close enough to the nub of the matter, which is the set of beliefs which led to the arrest of a laundrywoman and her daughters because a couple of noble children had fallen ill. Borman senses that she is missing something. What’s actually missing here is a hard look at the mindset of the era, up close and personal.

Matters were indeed much more complex than chunks of the Malleus Malificarum can explain. Take the suckling familiars. Borman doesn’t seem to know that one possible explanation for Philippa’s breast-hugging rat is that to the Flower women, the creature was not a pet but a helpful household brownie, a homely fairy. Or take James I: a hammer of witches in Scotland, but in England, with Stuart alertness and flexibility, he changed his tune. Labelling James a witch-hunter in 1618 is simply a mistake; he exposed the Boy of Leicester’s claimed possession as fraudulent in 1616, saving five women from jail, and condemning the judges at the trial for their superstition.

These problems are a pity, because the Flower case is a compelling one, and the book contains some fine attempts to illuminate the context in which the events took place. Borman delves into the lives of laundrywomen and other servants, sniffs out poison, and sympathetically discusses the misery of child mortality. An account of the human experience of being interrogated and tried for witchcraft in the early 17th century is spine-tingling reading.

With no chance to defend themselves, no defence lawyer, no hope of understanding the rules, and nobody to contest the judges’ views, the Flower women never stood a chance. Such careful reconstruction explains the desperation of the mother, Joan, who opted for some kind of trial by ordeal, eating blessed bread and then dropping dead immediately. On 11 March 1619, in the city of Lincoln, her daughters were hanged. History has ensured that not even Borman’s diligence can give them their long-overdue chance to explain themselves to us.

Diane Purkiss’s books include ‘The English Civil War: a people’s history’ (Harper)