It’s not hard to understand why Christmas is such an appealing subject for writers. The ingredients for drama – and melodrama – are all there. Reunions, big gatherings, financial and social pressure: feelings run high during the festive season.

Deirdre Purcell's new novel, The Winter Gathering, begins with an unusually dramatic Christmas. It's 2002, and the novel's narrator, Maggie Quinn, returns from Christmas shopping to find that her husband, Derek, has left her. A stunned Maggie faces the prospect of a bleak midwinter with no company but that of her mentally ill younger sister, Chloë, who lives with her.

But then her old friend Mary, a warm-hearted, no-nonsense woman, comes to the rescue. Maggie’s husband may have abandoned her, but her friends haven’t. So Maggie is joined for Christmas dinner by the reserved Lorna, a widow with a tangled family tree, cosy Jean, a keen knitter and charity activist, and glamorous Dina, who is still looking for Mr Right. Further disaster strikes when Chloë attempts suicide, but Maggie’s friends rally round her.

A decade later Maggie’s world has stabilised, not least because her “club” of friends are still together, and still meeting every Christmas. But 2013 will bring dramatic change into all their lives. Family ties are both forged and broken, serious illness forces a re-evaluation of relationships and romance will be found in unsurprising places.

These are all the ingredients of what could be classic commercial fiction, the sort of thing Maeve Binchy always did so well. But unfortunately The Wintering Gathering doesn't work. Maggie's slightly gossipy tone should create an intimate feeling, but instead the narrative feels unfocused and incoherent.

And although Purcell shows the real importance of friendship, the relationships don’t quite work. Maggie and Mary’s relationship rings true, but this is because they’re the only members of the group we really get to know. Lorna, Jean and Dina never come to life, and as a result the group dynamic isn’t totally convincing. And though Maggie’s concern for Chloë feels real, Chloë herself doesn’t.

In fact, one of the most believable relationships in the book is between Maggie and her delightful dog, Flora. Maggie’s love for her pet and Flora’s significance in her life are nicely drawn.

Purcell also writes about female childlessness, voluntary or otherwise, in a compassionate, refreshingly unsentimental and unpatronising way. But in other parts of the book it feels as though she is talking down to her readers. When Maggie tells us that Chloë isn’t attending the latest Christmas bash because she can’t handle social occasions, she adds: “I know that’s difficult to understand, particularly when the event in question is such a joyful one.”

But is there anyone who isn’t aware that Christmas can be a stressful time, not least for the mentally ill? And the down-to-earth tone doesn’t stop Purcell rendering the dialogue of some working-class characters in an offensively patronising phonetic style, adding pronunciation hints in square brackets in case we couldn’t quite imagine the accent: “We’re goin’ to skip Belgium. Scooh right t’rough it. We’re noh interested [‘inther-ested’] in Belgium. Thah righ’ Jeanie?”

By the novel’s end Maggie is looking optimistically towards the future. Yet as far as this reader was concerned, her story, despite its promise of sparkle and real emotion, was ultimately a flat disappointment. But then Christmas sometimes turns out like that.

Anna Carey's third book is Rebecca Rocks.