Sir Simon Rattle’s all-Ravel prom with the London Symphony Orchestra opened with magic but then, as happens in fairy tales, it lost its way. Ravel’s unadorned style of composition –dépouillé, as he himself described it – is not an invitation to add what’s missing but a musical language in its own right. Rattle, alas, seemed reluctant to trust it. He over-fussed in Shéhérazade and L’Enfant et les sortilèges and there were other problems too, of which more anon.

Hopes were raised by a diaphanous performance of the orchestral version of Ma Mère l’Oye (Mother Goose), a burnished pleasure that was played less like a ballet than an episodic tone poem. There was beauty from the outset as the orchestra spun Ravel’s Prélude out of clouds and memory, and the controlled delicacy of the virtuosic playing was a miracle of sostenuto. Not even the most intrusive spectator sneeze in memory could jolt the LSO’s rapt interpretation as it infused the Royal Albert Hall with delicate aromas of sweetness, nowhere more than in the fifth tableau’s exotic Gamelan material.

If Mother Goose was a sophisticated pleasure, Shéhérazade was a disappointment. Magdalena Kožená, a.k.a. Lady Rattle, took her lead from the child-centred music that preceded and followed Ravel’s cycle and eschewed sensuality in favour of innocent simplicity. This was most odd given her comment in the programme: "For me, this is one of the most erotic pieces ever written". For me too, so what went wrong? 

Kožena declaimed the intoxicating texts of Tristan Klingsor (the Wagnerian nom de plume of the poet Léon Leclère) with only a perfunctory attention to their sinuous languor. She was not helped by her husband’s sluggish interpretation of the score, nor by her obvious strain up in the music’s soprano range. As a live experience it was banjaxed by her less-than-insinuating timbre and, crucially, by the fact that barely a word was decipherable. The third song, L’Indifférent, is a cougar number that’s heady with sexual allure, but you’d never have known.

The first half’s various qualities, the good and the bad, all came together in the concert performance of Ravel’s short opera L’Enfant et les sortilèges that closed the programme. The Proms surtitles came into their own and prompted many a chuckle, although singers like the underused Elizabeth Watts and David Shipley sang in exemplary French and with such clarity that in their case they were only needed for translation purposes.

Anna Stéphany and Sunnyboy Dladla made a splendidly matched tea set, she as the Chinese Cup, he as the Teapot, while Gavan Ring injected humour and colour into the impossible blurtings of the Grandfather Clock. Patricia Bardon was equally characterful as the titular Child’s Mother, but in her showstopping moment as Fire the coloratura soprano Jane Archibald was disappointingly restrained, as though held back by her conductor’s over-cautious dynamics. An added quibble: were the massed muscular ranks of the London Symphony Chorus not a shade too emphatic for this filigree score? A small semi-chorus would have slotted into the sound world more agreeably.

Rattle’s interpretation was rich in colours – the Cup and Teapot’s Gershwin/Weill-infused music rollicked beautifully – but at other times he was too interventionist for the music’s good. Neither he nor Kožena could resist a tendency to add sentiment: a tempting choice, no doubt, but an idiomatically questionable one. Their shared problems were crystallised in the mezzo’s closing utterance of “Maman”, a normally heartstopping descending fourth that Kožena romanticised with a calamitous portamento.