There are two very strong memories: George Benjamin insisting on playing me the fifth movement of Turangalîla on an LP when we were students together (I thought it sounded like cosmic carousel music, beaming out of a tiny little record player) and, a couple of years later, seeing John Ogdon play Vingt Regards.

By that stage I played a few movements myself, but I was immensely moved by Ogden’s emotional fragility and virtuosic strength dealing with this huge work. It was a complex experience for me.

How universal, in your view, is his appeal? Is this music for children or does it require adult perspectives?

The length of some of his pieces or movements probably creates a problem for children; but in my experience young children absolutely love something loud, dissonant and exciting. There’s a thrilling amount of colour and swirling movement in many of his works, to delight someone young – Joie du sang des Étoiles being one example. And anyway there are many entry points; I would have thought that the story of the first performance of Quatuor pour la fin du temps would fascinate teenagers working on World War II, and along the way they’d find some of that music enthralling. I think most of us can’t take in everything, immediately.

What of its challenges to the performer? Are there particular challenges unique or definitively peculiar to Messiaen?

For pianists, if you’ve played Bach, they’ll be resonances in Messiaen’s constant fascination with numerology and counterpoint. It doesn’t make the music dry, but it gives it fantastic, Gothic architecture; the music is always underpinned by foundations that are rock solid. There are flashes of Liszt (see the climax of, say, Le Baiser de l’Enfant-Jésus) and of Mussorgsky: George told me that the two operas he wanted his students to study were Pelléas et Mélisande and Boris Gudunov. Yvonne Loriod was known as a Mozart player when Messiaen first met her; by fourteen, she performed all of Mozart’s piano concertos; even in her sixties she wistfully wished she was asked to perform them all again (she was his muse, and forever attached to his enormous piano writing; I don’t think it occurred to any promoter to ask her to play something else.) But I often think about that when I play Messiaen, about Loriod’s tremendous classical hinterland.

But there are two things that will always be a challenge when first playing Messiaen: the size and speed of his chords (those modes do become second nature, eventually, but only after several years); and his asymmetric rhythms. Messiaen was deeply immersed in Greek and Indian rhythmic patterns, right from the start, and it takes time to convey these with naturalness. They shouldn’t ever sound stuck or ‘difficult’. I got hold of his monograph Technique de mon language musicale while I was still a student – and he lays open his style and influences very transparently, with many examples. Highly recommended – you can practice your French too! (Although I think there may be an English translation online these days.)

Some people might mention physical and mental stamina in regard to performing Messiaen’s works (Turangalîla is 80 minutes, Vingt Regards is two and a quarter hours without a break; even Quatuor is fifty-five minutes. But I think this is part of a long tradition; I think of The Art of Fugue, Goldberg variations, Diabelli Variations. As well as Wagner and Bruckner.

What is the extent of his emotional/spiritual/expressive range?

I hope you won’t mind if I quote my opening liner notes on Vingt Regards here:

Vingt Regards is massive, almost unruly in its overflow of energy and colour, teeming with gorgeous sonorities and intellectually rigorous ideas. Each movement is quite literally a meditation on a theological aspect of his Roman Catholic beliefs, yet the contemplations are meticulously and dramatically paced: they can be serene, fierce, languid, rigidly doctrinal or even humorous. The nearest equivalent I can think of to the contradictory forces held within some movements is the work of the metaphysical poet John Donne, whose Holy Sonnets contain surprisingly forceful imagery -‘Batter my heart, three-person’d God; for,you/As yet but knock, breathe, shine, and seek to mend’.

The other truly remarkable quality is Messiaen’s knowledge and love for Eastern music and philosophy. Like the American composer Lou Harrison, he challenges our Western notions of time and structure. The whole work of Vingt Regards may well represent the austere and magnificent edifice of a Gothic cathedral, but the detail and pacing of each movement owes much to Hindu rhythms and the sonority of the Balinese Gamelan.

….Every time I return to the score of Vingt Regards, I am amazed that a work so ambitious and diverse can be built upon unifying building blocks that are in themselves so simple and repetitive. In that sense there is much in common with Bach’s The Art of Fugue, which is equally intellectually rigorous, built on one unadorned fugue subject in D minor. The unifying key in Vingt Regards is F sharp major, heard in hushed tones at the opening, and thunderously at the end. F sharp major, both as a straight tonic chord and with its more luxuriant added sixth, stands almost as an icon throughout the work.

….. Certainly in these pieces we really see Messiaen’s view of God, his Son, the Virgin Mary, Angels and birds  – but we see far beyond the material world and begin to contemplate abstract ideas, as well as feel the passion of Messian’s beliefs, rooted in sensuality as well as theology. Sometimes ‘regard’ is translated as ‘adoration’, but even Messiaen added often quite impressionistic subtitles in an effort to explain the title; he sometimes expanded on the structure of the music and the implied iconography. There are many ways to appreciate Vingt Regards – as a technical achievement, an act of faith, an emotional rollercoaster. It is a tribute to the depth of this masterwork that its meanings are as infinite as all the global references Messiaen draws upon.

Messiaen’s music is quite troubling precisely because it isn’t binary; it holds Catholic dogma alongside wild rapture, and often the most lengthy pieces are built on simple ideas and repetitions. Some familiarity with poetry of the Book of Revelation is useful, and a willingness to live in the stratospheric, occasionally circular world of birds. There’s a handful of works that have definitely entered the mainstream – Vingt Regards, Quatuor, Turangalîla but I hope eventually others will be more frequently played too, like the ravishingly beautiful Couleurs de la Cité Céleste, the song cycle Harawi, the Stravinskian Oiseaux Exotiques, and Et Expecto. Also his most compressed, soulful and succinct birdsong writing, the very late Petites Esquisses, almost his last gift to his wife.