Although widely recognised as a fin-de-siècle masterpiece, Debussy's Pelléas et Mélisande rarely makes it into the opera house. When it does, it is frequently cluttered with heavy-handed directorial concepts and curious set designs. These elements are unnecessary: much of the interest lies in the psychological element of the work, with Debussy's score externalising the allusions captured in Maurice Maeterlinck's enigmatic text. The approach taken by the Philharmonia at the Royal Festival Hall was much more successful as an alternative: a concert performance with a few subtle additions to highlight certain aspects of the work. With the Philharmonia on top form, a stellar cast and minimal staging, this was a truly magnificent interpretation of the opera.

The performance began with the cast sitting in the choir stalls, white masks covering their eyes: a nice touch, given the principles of concealment and revelation which characterise the Symbolist work. Movement was minimal, with the characters drifting down to the front of the stage for each scene, and back again afterwards; this created a wonderful dreamlike feel, meaning that the navigation of space (often an issue in fully staged versions, given the static nature of the scenes) was not a problem. The masterstroke of the performance, though, was Colin Grenfell's lighting. Utilising orange and blue-violet colour washes and spotlights, he brought out the evolving moods and underlined certain ideas while making explicit the references to light and darkness in Maeterlinck's text. This simple idea was enormously effective, further intensified some of Debussy's most stunning passages and added to the ominous mood underpinning the work.

Placing the Philharmonia on stage completely transformed the work. No longer were the orchestra the muted backdrop (as they so often can be in this work), but complicit in the drama: expressing the implied, their prominence on stage allowed the emphasis of their importance to the plot. Indeed, Esa-Pekka Salonen seemed keen that the orchestra should play a central role, bringing out bold colours rather than pastel shades, but without sacrificing nuance and sensuality. Such vividness was particularly significant for a work often considered to lack action: while retaining ebb and flow, Salonen's taut conducting meant that the work was tense and gripping. The Philharmonia sounded fantastic, bringing both clarity and voluptuousness to Debussy's score. The orchestral interludes seemed almost symphonic, yet translucent and elusive.

The cast were no less deserving of superlatives. Sandrine Piau was an exquisite Mélisande, with her performance especially impressive in view of the fact that she took the place of an indisposed Monica Bacelli at the last minute. Piau's shimmering, crystalline sound lent a purity and fragility to the enigmatic figure, and her hauntingly beautiful 'Mes cheveux longs' was undoubtedly the most memorable moment. Stéphane Degout's Pelléas was rich and full, with wonderful diction, while Laurent Naouri's Golaud was virile and powerful. Dame Felicity Palmer, Chloé Briot, Jérome Varnier were no less outstanding.

Each act was bookmarked by entr'actes narrated by Sarah Kestelman, created from Maeterlinck's own words by Gerard McBurney. Musing on the nature of art and the events which had taken place, they provided an interesting insight into the poet's mind. However, I found that these palette-cleansers somewhat interrupted the flow of the music; couldn't they have been published as a series of miniature essays instead?

Ultimately, though, such a point was trivial. This outstanding interpretation of Pelléas et Mélisande cast into doubt the work's association with the opera house: this particular performance did the opera justice, while bringing the house down. If this concert was anything to go by, attending the rest of the Philharmonia's City of Light: Paris, 1900-1950 season will be essential.