If a prologue to a novel is to whet the reader's appetite, Louise Doughty provides irresistible temptation with the opening of Apple Tree Yard.

The narrator is in court, in the witness box, sweating and hyperventilating as she realises that, with the next question put to her, "it is all about to tumble". The author has provided a consummate demonstration of one of the tips she gives to aspiring novelists: "A good trick for kick-starting a narrative is to have a situation that makes the reader ask, what is going on here?"

In this, Doughty's seventh novel, the answer is something very serious. The court in question is the Old Bailey, although what criminal act led to this moment of courtroom drama, or even whether the central character is the perpetrator or the victim, is not revealed until the reader has accompanied her through the chain of events that led to this downfall.

As in any narrative of the heightened emotions of an illicit love affair – of any love affair – these events are a juxtaposition of the extraordinary and mundane. In this case, the entire construction depends on an event which is both unprecedented in the life of the narrator and commonplace as a literary device. This is an act of adultery, given additional frisson by taking place in a cupboard in the Crypt Chapel of the House of Commons between two people who have only just met and not yet exchanged names.

Since it happens in the first chapter, the reader is similarly swept up in the moment. Yet it is difficult to completely dispel a nagging disbelief in this unlikely coupling, despite being carefully prepared for the inevitability of a coup de foudre from the moment our middle-aged heroine locks eyes with the good-looking man in the Westminster corridor. It is a testament to Doughty's narrative power, however, that with this as the basis for a dark exploration of the consequences of deception, it remains a compelling read.

First-person narration allows the central character to reveal herself to the reader in carefully controlled stages. At first we know her only as Y, a geneticist, wife and mother, apparently comfortably settled in the London suburbs with her scientist husband. With the revelation that their marriage is now sexless, their twin studies in the attic seem to symbolise parallel lives rather than domestic bliss.

The tale develops both pace and credibility as Y becomes Yvonne and we are privy to the end of an affair between her husband, a kindly man whom she genuinely loves, and a young colleague. So an element of revenge may explain why Yvonne, the geneticist who gives evidence to parliamentary committees and "not the sort of woman to throw caution to the wind", engages in a reckless affair with a man she barely knows. It leads (albeit indirectly) to violence and a chain of destruction but the process of this transition, psychologically and morally, is as engaging as the page-turning events.

Recollection, interspersed with the growing tension as the trial plays out in the Old Bailey, provides a perfectly dovetailed structure. But within the thriller framework lies a wealth of acutely observed detail, a dissection of social attitudes and an examination of lust, trust, predatory sex, risky behaviour and responsibility.

All this, however, is served up in a bold, challenging manner that dispenses, unapologetically, with customary niceties of character delineation or scene-setting. Although this focuses attention on the central couple, it can be frustrating. Even Yvonne's lover, who remains nameless for much of the book, is a largely unknown character. This arrangement, however, consciously mirrors the unknown elements of the initial sexual encounter in the Chapel below the House of Commons. As deftly as her lover lured Yvonne into a high-risk relationship, Doughty has skilfully led the reader to cast aside misgivings and trust her confident lead. That the result is unsettling is evidence that there is considerably more to Apple Tree Yard than thrilling narrative alone.

Apple Tree Yard

Louise Doughty

Faber, £12.99