Despite knowing what was going to happen, it was a still surprising when, amid the chatter and bustle of the audience before the concert (there was a distinct lack of communal coughing before it started), the National Youth Orchestra of Great Britain began Tuning Up. Edgard Varèse’s piece is a veritable romp, and this orchestra really went to town on the performance – hamming up the jokes and, somewhat bizarrely, acting out greetings to players who had made jaunts into the audience to crank the air-raid sirens, whose presence was perhaps the most interesting feature of the piece. Sketched in 1946 (and only completed by Varèse’s student in 1995), a post-war audience would have heard more humour and pathos to the interrupting gestures of the sirens than the audience tonight, when these gestures were reduced to non-sequitur status.

In this short half all that was left was Nico Muhly’s commission, Gait. At the relatively tender age of thirty, Muhly has found success with high-profile institutions and projects; for example, his recent collaboration (with just about everyone) to create a ballet based on Titian paintings premièred in July. This piece didn’t quite satisfy over its longer-than-usual (for a Proms commission) 20-plus minutes, as its repetitions bore little fresh fruit and the second half struggled to shake off a harmonic paralysis. In the opening section material developed organically and several moments shone through – woodwinds blending with strings whilst a solo trombone theme emerged (think Sibelius’ Seventh Symphony), as well as a paragraph for the delicious paring of tuba and piccolo. The orchestra performed admirably, though the strings felt a little flabby and sectional balance was not always maintained. At the interval Muhly’s take on developing minimalism was perceptively summed up by my guest as “So Reich it’s wrong”.

Messiaen’s Turangalîla-symphonie is massive. It’s also a masterwork. Having heard of this piece more than having heard it, I eagerly awaited hearing its 10 movements live, and how the ensemble would cope with so unwieldy a score. To start with, the percussion section must be singled out – they showed surprising confidence playing a part littered with potential booby traps. The strings summoned a much tighter sound than earlier, articulation precise and timing impeccable, all held under the crisp and articulate conducting of Vasily Petrenko – who I couldn’t help but feel left a little in the tank, maintaining a slight reserve that ensured accuracy but didn’t quite let the orchestra squeeze out the last drops of this achingly emotional piece. The sixth movement is one of the loveliest things I’ve heard in a very long time, with its langourous tunes over muted, lilting accompaniment and ethereal gestures from woodwind and percussion. Its effect eventually led towards the soporific when combined with the heat in the Albert Hall.

Because of the intensity of Messiaen’s symphony I was dubious about the inclusion of Anna Meredith’s HandsFree at the end of the programme, and I maintain it would have made for a more balanced programme to place it at the end of the first half. Nonetheless, Meredith’s instrument-free contribution to the New Music 20x12 project was an interesting inclusion for the Youth Orchestra – and showcased a performance few other ensembles would make convincing. The joy of the ego-less teenagers in this orchestra is their willingness to try, without judgement or cynicism, a performance practice well outside the usual comfort zone of a classical orchestra. In two distinct parts, it’s fair to say that the visual effect was more powerful than the aural as the players slapped, clapped, clicked and barked their way through 12 minutes of most unusual music. It was a shame to see some of the audience leave through what they must have considered an experience of music they were above. The second half of this concert in particular proved what an exciting event in the Proms calendar the National Youth Orchestra’s concert can be.