Sir Simon Rattle is an uncommonly gifted conductor of early 20th-century French music – Debussy, Ravel, and the like. The intrigue of this concert, then, radiated not from the rostrum but mostly from the orchestra itself. Playing with ‘period’ practice – though what that entailed was explained neither during the concert nor in the programme note – the Orchestra of the Age of Enlightenment and Rattle continued to press new ground, following on from their Prom of Berlioz and Wagner a few years ago with even more modern fare. Other period groups have gone just as far into the twentieth century – I’ve heard Britten and Finzi, of all composers, on gut strings – but few have dedicated entire programmes to such an endeavour. And why not, if something special emerges in performance to justify it?

As it turned out, these ears could not decipher much of a difference between these OAE performances and live recordings directed by Rattle with the Berliner Philharmoniker. There was, clearly, the gulf between a very good and a truly great orchestra, although the OAE’s playing here was fully committed. With the first chords of Fauré’s restrained suite from Pelléas et Mélisande there was an instant warmth, the OAE’s strings luxuriating in being let off the vibrato-less leash. And even if that warmth was surprising (and welcome), there was not the pure depth of tone one might hear from other, ‘modern’ string sections, particularly low down in the register. There was far more colour to be found in the Ravel concerto and especially in a superb La mer, but there was little that distinguished these performances from others one might hear in terms of sound – except some rather wayward tuning and piping peeps from the woodwind (especially the principal oboe, who has had better evenings). Indeed, in La mer it could very easily have been forgotten that this orchestra was employing ‘period’ practice at all. Whether that stands as a nod to the unalloyed success of the performance or as an indictment of the whole enterprise will rather depend on where one stands in relation to ‘period’ performance more generally.

The Fauré was the least convincing orchestral performance here, mostly because the piece relies much more on a carpet of delicate, throbbing string sound than the other three works (particularly in the ‘Mort de Mélisande’ conclusion). Still, there was some marvellous playing, even if the colours deployed were more thin watercolours than vibrant acrylics. The ‘Fileuse,’ in particular, neatly juxtaposed busy undercurrents with surrounding prim, tragic lyricism.

The Ravel, with Pierre-Laurent Aimard playing a gorgeous Érard piano (complete with matching stool), was much more successful. Rattle’s control of Ravel’s episodes was sure, especially in the beautifully degredated crescendo before the piano’s first entrance. The colours, too, were much more telling than in the Fauré, particularly in the winds and brass. There was a mechanistic sense about much of the playing (almost like the Boléro), perhaps reflecting the war-induced, left-handed needs of the piece’s commissioner, Paul Wittgenstein. Aimard’s Érard, tenderly but never sentimentally played by this most intelligent and erudite of pianists, was the star here, its hazy timbres and seductive subtlety adding a great deal to the piece when compared to a brighter Steinway. The encore, Debussy’s Les sons et les parfums tournent dans l’air du soir, had a similar effect, the colours quite different without a Steinway’s cosseting purity of attack.

It was in the Debussy, as ever with Rattle, that things really took off. The Prélude à L’après-midi d’un faune was perhaps a little on the languid side, the muted horns making up for some slightly breathless flute and oboe work. La mer, though, was in a completely different league. Rattle’s talent for bringing out details and working them into a cohesive whole illustrated the braying of the gulls, the popping of spray, and even if there wasn’t the last ounce of sheen to the string tone light still glinted from the wavetops. This was a daring reading, exhilarating especially in the outer two movements. It had as much drive and – say it very quietly – as much colour as this conductor would extract in an excellent performance from his home band. For me, that was probably down to Rattle's prodigious abilities in this music: it was questionable whether the OAE brought anything out of the mainstream to the soundworld. Still, an excellent conclusion to an undeniably interesting concert.