The Horror of Love, By Lisa Hilton

At the heart of Lisa Hilton's new book is the relationship between English writer and teasing perpetrator of the U- and non-U debate of the Fifties, Nancy Mitford, and her long-term lover, the French Resistance fighter and later minister, Gaston Palewski. Like that relationship itself, from time to time this heartbeat is difficult to discern. Over three decades, Mitford occupied a singular but not the single place in Palewski's roving heart.

Hilton denies that The Horror of Love is a "Mitford book"; her intention was rather to write "the biography of a love affair". Given the seeming absence of personal statements by Palewski about his relationship with Mitford, and the arch, evasive, stiff-upper-lip attitude she diplays in surviving letters to "the Colonel", Hilton is forced on to the well-trodden paths of Mitford lore – all "shrieks" and "teases" and verbal jeux d'esprit – alongside a re-examination of several of her novels.

It is this textual archaeology which differentiates the present book from earlier accounts of Mitford's life. With the exception of an intriguing but unconvincing connection between the poetry of Lovelace, The Pursuit of Love and Mitford's feelings for Palewski, it successfully reconciles the reader to a suspicion that, disclaimers notwithstanding, Hilton is having her cake and eating it. The Horror of Love does contain a portrait of a love affair and Hilton is stout in her assertions that (although Palewski married someone else) this relationship was based on love. Like the subtext of much of Nancy Mitford's fiction, it makes for bittersweet reading.

Palewski and Mitford were united above all by a love for France and all things French. Both shared a vision of French sophistication, which emphasised the refinement of the 18th century, a decorative if sexually indecorous period of aristocratic complacency which appealed to Mitford's conservativism, Palewski's social aspirations and their shared aestheticism. Given these tendencies, their relationship inclined to fictionalisation even in life: it was for both a form of escapism. Once Mitford wrote "the Colonel" into her novels, most famously The Pursuit of Love, their affair acquired a fantasy element: a fragile foundation for happiness.

Palewski was of Polish Jewish origins. De Gaulle's right-hand man, he achieved distinction in postwar French politics and as an ambassador, although neither a diplomat nor a politician. A notably ugly man, with "a face like an unpeeled King Edward", he possessed overwhelming sexual charisma and indulged his facility for seduction on a grand scale. Throughout their 30-year affair, following their meeting in London when Palewski was organising the Resistance, he was consistently unfaithful to his English mistress.

There was nothing covert about his philandering and Mitford responded by hardening herself to what she regarded as a French attitude to romance: the distinction between happiness in love and sexual fidelity. Hilton's account of Mitford's struggle to achieve this equilibrium – which mirrors that of her heroine in The Blessing – does much to counter the view that she was cold-hearted and unfeeling.

The charm of The Horror of Love is its bringing to life the worlds of Nancy Mitford's novels. Its portrait of upper-class postwar Paris, Palewski's femmes du monde extravagantly garbed in Dior's New Look, Mitford and Palewski's shared love of history, paintings and antiques, the glittering parties in splendid houses and the regular recurrence of the Duchess of Devonshire, will surely appeal to Mitford fans, in this book which delights in the more picturesque aspects of its subject.

Matthew Dennison's 'Livia: Empress of Rome' is published by Quercus