Not being a French national and having only just heard about their excellent series of Tuesday night concerts, this was my first visit to the Institut Français, Kensington. This was the last in a series of concerts focusing on French music, moving chronologically toward contemporary/modern composers over the course of the series. It was a shame then that only 40 or so people had made the trip to see the Mercury Quartet (a mixed-instrument group who are hot property at the moment, as part of the cool set signed by the wildly proactive Nonclassical record label).

The quartet were introduced by composer Julian Anderson, who intoned the merits of the Boulez piece we were about to hear, asking the ensemble for snippets to outline the points he made. Whilst interesting, the delivery was decidedly bland and this, combined with the very low turnout and the intense heat of the room, contributed to a rather staid and stuffy atmosphere. Fortunately the vibrant ensemble sound that opens Boulez’s Dérive I, for the unusual combination of flute, clarinet in A, vibraphone, piano, violin and cello, was enough to snap the audience to attention.

This piece, written during a relative drought in Boulez’s compositional output (he completed only six pieces in the 1980s), feels much more accessible than some of the more austere pieces from the early part of his career. The opening is punctuated by conspicuous trill/tremolo gestures that move around the ensemble before combining to create unusual and gripping textural effects. The exploration of the instrumentation is this piece's real triumph – the soundworld invented and excavated is tantalisingly exotic. The rounded vibraphone attacks stand out against increasingly manic and broad-brush ensemble gestures, before the pace calms down and the six chords the whole piece is based on begin to rotate in varying combinations. None of the effects asked for could come off without an ensemble playing ‘as one’, and the Mercury Quartet with extra flute and vibraphone (conducted by Robin Green) exuded a tightness that allowed the audience to relax into this short but intense piece.

I’m a fan of Gérard Grisey’s music, but hadn’t heard the important 1986 work Talea before, so was excited to have the opportunity. All music should be heard live but the music of the spectralists (a movement that Grisey refused to acknowledge but that he was at the heart of creating) really can’t be heard any other way. So much is predicated on instrument acoustics and the interaction between complex sounds in a real space that speakers simply won’t do. For that reason, a little was lost in the dull acoustic of this venue, a cinema. Its cloth seats and carpeted walls that do so much to help with a cinema experience dampened the musical effect somewhat, and this is perhaps why this piece left me a little disappointed. There was a lack of the clarity which marks Grisey’s other music and makes it so satisfying. Split into two sections, the first rattles along at an unfamiliarly quick pace, and only when the (much longer) final section begins are we on the more familiar ground of slowly shifting harmonic fields. Here again the ensemble squeezed all they could from their unusual sonic combinations; balance was excellent (so difficult to achieve) and timing impeccable, as they breezed through some of the virtuosic contortions demanded by the composer. Come the interval, the only reason I was glad to extract myself was for relief from what had become an unbearably hot room.

The second half was filled with Messiaen’s Quartet for the End of Time. Written in a prisoner-of-war camp in 1940-41, much is always made of the rag-tag ensemble that premièred the piece (there are many apocryphal stories, mischievously spread by the composer himself, for example that the clarinet keys were melting as they performed under gas stoves to fight the cold). No such drama here: the Mercury Quartet is no rag-tag ensemble and they performed this piece sublimely. The closely knit ensemble played intuitively and with an emotional commitment that meant players were visibly moved after performing the extended solo lines that are an integral part of the piece. The solo clarinet movement, performed magnificently by Harry Cameron-Penny, is conspicuous in the structure of the piece and has such moving, immersive lines, evoking a strange, dispassionate sorrow.

This concert had a great deal to offer – a well balanced programme that highlighted the intricacy of Boulez’s, Grisey’s and Messiaen’s writing for specific, unusual instrumentation, as well as Mercury Quartet’s awesome togetherness and deft ensemble playing. The only downside was an acoustically inappropriate and soporifically hot venue.