Notes on a Scandal by Zoë Heller

Zoe Heller's second novel is a study in self-deception. Bathsheba Hart is a floaty-skirted, middle-aged pottery teacher from the privileged classes, struggling to assert that her affair with a grubby 15-year-old student is a genuine love match - even as his adolescent posturing and flippant cruelty suggest otherwise. Her protestations and refusal to see the affair from anyone's point of view but her own - not even from her lover's - are excruciating. But it is the narrator whose mangling of truth casts the more sinister shade.

Barbara Covett, a dusty spinster with a poky flat, old-fashioned views and the inevitable cat, is a classic unreliable narrator. The two are in hiding from the tabloid press, and Barbara, just retired, has undertaken to write an objective account of Sheba's downfall. "This is not a story about me," she writes. But, of course, it is.

To make sure that she "maintains maximum accuracy", the pragmatic Barbara - ever the history teacher - has created a "timeline". It's "just a little thing on graph paper", but she painstakingly marks key events with gold stars.

The first occurs when Sheba, "artfully dishevelled" and destined to be torn to pieces at the grim comprehensive, floats into the staffroom on a cloud of posh good intentions. She and her high-minded plan to elevate her students through art are doomed. Especially when sly Stephen Connolly, a lithe, "edible" 15- year-old, starts private tuition. "My fellow [teaching] students and I never thought of raising self-esteem or making dreams come true," tuts Barbara. "We might not have fretted about our children's souls, but we did send them out knowing how to do long division."

In the manner of judgemental types, however, Barbara reveals herself through her own caustic aperçus. Her crossness at the unreturned phone calls, her desperate insistence on being needed and the astonished nose-wrinkling at the detritus of family life, all reveal the emptiness behind her busybody industriousness. And, for all her insistence on their closeness, she and Sheba are chasms apart; separated irretrievably by class, the author implies, they don't understand each other at all.

"'Being alone isn't the worst thing...,' [Sheba] said. 'But it's funny, isn't it,' I said, 'how it's always people who aren't alone who say that?'... 'Not so funny,' said Sheba. 'Maybe they're in the better position to judge.'"

But lonely people do desperate things, and, just as we think we have the measure of Barbara, she takes a sinister turn. What rankles for the reader is that headstrong Sheba allows herself finally to need Barbara, whose act of jealous malevolence has reduced her to childlike dependence. The pathetic spinster has someone to care for, and she settles chillingly into the fishfinger-cooking role of the mother.

Although initially she seems a caricature spinster, Barbara is a figure of creepy complexity. Notes on a Scandal reads like a nose through someone else's bathroom cabinet: full of guilty insights and delicious snobbery. It will be uncomfortably familiar to anyone who has loved the wrong person, betrayed a friend, or ever been lonely.