Friday Nights, by Joanna Trollope

'This is me. I've been there": so tens of thousands of Joanna Trollope's devotees are said to respond to her portrayals of middle-class social breakdown. Her parish of assorted relicts – mistresses, widows, lonely wives and divorcees – is recognised by readers as adjacent to their own streets and stories. The novels foreground a chosen dilemma, then a cast of characters is assembled to illustrate the chosen malaise.

What is it that lends a Trollope narrative this reality effect? Her plots are mechanistic and top-heavy with theme; the relentless chatter of the dialogue can seem trite; character is sketched over a water-colour wash. Yet every Trollope novel contains some quality that that hits a right and ringing note, and keeps hitting it. In Friday Nights, this authenticity resides in the characterisation of the older woman, Eleanor, and the voices of the children and young people.

Friday Nights concerns the fragile alternative communities we forge from the casualties of modern life. Eleanor, a vigorous retired NHS administrator, has long observed from her Fulham bay window two lonely young mothers. Why not befriend them? To answer her own need for companionship, Eleanor assembles a circle of female friends who meet every Friday night. This radical step towards bonding is the novel's good idea, an experiment in community.

For modern neighbourhoods are only neighbourly up to a certain point. A neighbour, observes Eleanor astutely, "would gladly save you from a burning house but should not be expected to mend your broken heart". Hence the courageous and curmudgeonly, open-hearted and oracular Eleanor positions herself at the centre of a support group of her own convening. Within this group she thrives, and so do Lindsay (young widow), Jude (DJ and lost girl), Blaise (single professional), Paula (ex-mistress), Karen (married businesswoman) and their children.

This list exemplifies the problem. There are far too many emblematic characters. Their author everywhere exhibits a busy competence, moving them around like counters. The novel's people, communally representative of its theme and the choric agents of its plot, dare not get out of order.

Enter a man. Youngish, eligible, laconic and blokish, Jackson Miller is a subversive version of a Mills and Boon charmer or a vacuous version of Iris Murdoch's charismatically wicked enchanters. Jackson is there to disturb the waters: accordingly, he makes a manipulative progress round the group, disrupting the chain's links. The tedious arrival of this hunk fired me with hope that he might turn out to be a mass murderer. I was disappointed.

He is there to make monkeys of the women, notably Paula. "I'm a cliché ... aren't I?" she witters, purchasing outfits to allure her new man. Charming Paula's son, Toby, by taking him to Chelsea football ground; exciting Karen; riling her husband; infiltrating Jude's clubbing world, he completes his plot work and is voided, without benefit of characterisation.

Trollope is a naively expository author who scarcely seems to know her own strength. We want more of the fascinating Eleanor. It is the children who save the novel from bathos. Their poignant exclusion from the immature dealings of the adults gives them not only insight but closeness to the tragedy of utter abandonment. They endure chaos and speak with deadpan authority. Toddler Noah's cryptic construction out of household objects; Poppy's chorus of "Poo bum"; Rose's all-seeing antenna eyeballs, one in her sibylline mouth; Toby's "Fuck you", all voice the child's dire battle for survival. Trollope harnesses in the young the narrative power of the cryptic, forbidden to the self-helping and platitudinous adults.

Bloomsbury £18.99 (331pp) £17.09 (free p&p) from 0870 079 8897

Stevie Davies's 'The Eyrie' is published by Phoenix