In the third of a four-part series, Peter Reynolds looks at different strands in contemporary music with a focus on composers in the immediate here and now. This week he looks at five composers whose music occupies the challenging end of the spectrum.

The last 20 years have seen a retrenchment from the heroic experimentation that characterised contemporary music in the immediate post-war years. A generation of composers growing up amongst the carnage of Hitler’s Europe turned their faces away from the traditional language of music, which seemed forever tainted by that world, in search of a new musical grammar. But successive generations, without such memories, have been more inclined to take what they want both from the latest developments and the past.

The debate still rages as to whether such a retrenchment is a cowardly betrayal of the zeitgeist or the natural splintering of a more pluralistic society. Many of the architects of the post-war revolution – Stockhausen, Berio, Nono, Xenakis, Ligeti, Carter, Cage and others – are now dead, but there is still a powerful strand of composers, utterly uncompromising in their search for a new sound world, making huge demands on listeners and performers in their efforts to move music forward. A sceptical public and musicians have dismissed such music with expressions like “squeaky gate” but it is undeniable that the avant-garde of the past has influenced popular culture, jazz, crossover and even the most conservative classical composers.

Pierre Boulez launched the post-war musical revolution in Paris in the late 1940s. Declaring that “anyone who has not felt the necessity of serialism is useless” and that opera houses should be blown up, he metaphorically spat on the grave on Schoenberg in his iconic 1952 polemic “Schoenberg is Dead”. His Le marteau sans maître (1955) was as influential as Stravinsky’s The Rite of Spring 40 years before. Boulez also went on to become a world-class conductor and instigated Paris’ IRCAM, revolutionising the development of music technology. Consequently, his compositions appear infrequently, but even his detractors (and they are many) agree that his music is unmatched in its fastidious finish and subtlety.

Watch an interview with Pierre Boulez

 Listen to clips of Pierre Boulez’s music

Over the last 30 years, London-born George Benjamin has been uncompromising in taking music into new and uncharted territory. Like Boulez, he made his way to Paris in his teens to study with Messiaen, haunting the corridors of IRCAM in the following decade. He shot to prominence at 20 with his Ringed by the Flat Horizon at the 1980 Proms and, despite his small, highly polished output, he has rarely been absent from the concert halls since, particularly in Europe where he is regarded as a major figure. In recent years Benjamin has caught the opera bug and his recent Written on Skin, at the Royal Opera House and elsewhere, has seized the attention of a large public.

Watch an interview with George Benjamin about his opera Written on Skin

Watch an interview with George Benjamin about his teacher Olivier Messiaen

 Listen to clips of George Benjamin’s music

In 2013, Proms audiences basking in the lush romantic certainties of Mahler’s Fifth Symphony also sat through the music of 77-year-old German composer Helmut Lachenmann. With the deaths of Stockhausen and Henze, Lachenmann is now the grand old man of German music. In his scores instruments are rarely played conventionally, his music occupying a subtle twilight world between scrapes, scratches and sighs and silence. Yet it is an utterly seductive world, and works such as his Third String Quartet are among the wonders of contemporary music, albeit a world so far removed from the traditional string quartet as to be barely recognisable as the same ensemble.

Watch an interview with Helmut Lachenmann

When Jonathan Harvey died in 2012 there was a real sense of regret at his passing: a composer at the height of his powers. Each new work seemed better and more radical than the last, combining a spectral extension of traditional instruments with cutting edge technology. Yet what one takes away from the Harvey’s music is an inner spiritual experience. Steeped in Buddhist-inspired spirituality, he explores a realm of pure feeling and states of heightened awareness on the borderland between consciousness and unconsciousness. Technology is never used as an end in itself, but as a way of taking music into other realms of space and time, to go beyond physical boundaries. He may well turn out to be the one of the most important British composers of the last 50 years.

Watch an interview with Jonathan Harvey

Find out more about Jonathan Harvey

Brian Ferneyhough’s music takes complexity to new extremes, aiming at a transcendental virtuosity in which the performer is given more information than it is possible for him or her to realise. Inimitable, he has spawned a whole movement, known in the late 70s as “the New Complexity”, but few can match the sheer daring of Ferneyhough’s scores, be it La terre est un homme, in which each member of a symphony orchestra is given an individual part of staggering virtuosity, or Time and Motion Study II, where a solo cello is presented with a five-stave score with parts for both right and left hands, two foot pedals for electronics and a vocal part. It is still too early to predict how history will regard Ferneyhough – as a wild wilful genius or as a product of English eccentricity.

Watch an interview with Brian Ferneyhough

For more information, check out Tom Service’s Guide to Contemporary Classical Music for the Guardian, or visit the Sound and Music website.

This article was amended on 05/01/2017