Heartburn, Radio 4

How a few choice words can skewer an erring spouse

Cinema critics tend to be sniffy about voiceover narration, the idea being that dialogue and images should be sufficient to tell the story. I'm not so sure: some of my favourite films – Trainspotting, GoodFellas, A Clockwork Orange, to name three masterpieces – are all the better for it. In his screenwriting bible, Story, Robert McKee rules that if the voiceover is removed and the film still makes sense, it can be left in: narration as counterpoint is acceptable.

That sounds too prescriptive to me. At their best – and without necessarily being contrapuntal – film voiceovers build atmosphere and feeling, providing insights that might not otherwise come across in straightforward dramatic exposition. That's even more applicable on the radio, where we're used to pieces that convey the internal lives of their subjects, and it's certainly the case with Heartburn, the semi-dramatised adaptation of Nora Ephron's roman-à-clef broadcast in daily chunks on Woman's Hour and repeated as a stand-alone in the evenings.

The tart voiceover is by the central character Rachel Samstat, a cookery writer in Washington whose columnist husband – based on Ephron's ex, Carl Bernstein – runs off with the wife of the under-secretary of state in charge of Middle Eastern affairs. It carries the central thrust, with the dramatised bits adding colour. "Cooking became the easy way of saying I love you," Rachel says. "Then cooking became the only way of saying I love you. Would anyone love me if I couldn't cook?" That would take pages of drama to convey. And again: "My first husband was so neat he put hospital corners on the newspaper he lined the hamster cage with." Long pause. "I left Charlie after six years." Job done, first husband skewered in two sentences. As for the second, Mark, he's "a fairly short person" philandering with Thelma, "a fairly tall person". Ouch.

The drama is good, too. Rachel is in group therapy to get over Mark's infidelity. "I want him dead," she announces. "I thought you said you wanted him back," the therapist says. "I do want him back. I want him back dead."