A sea of white shirts, red ties, fresh faces; and more woodwind and brass than you could muster for the average wind-band convention. The annual Prom visit of the National Youth Orchestra of Great Britain is always a heartening event, an indication - albeit a small one - that the tradition of live music-making in this country still has a future. You may ask yourself, based on these results, why the opportunities are not more widespread, why music teaching in schools is still the exception not the rule. But at least it's an annual reminder of just what is possible given the will and the way.
Sir Roger Norrington was the man with the baton this year, the man charged with convincing us yet again that there can be safety in numbers. It's a tall order maintaining balance and co-ordination with a band of this size. Turning corners can be a nightmare. Three movements from Smetana's Ma Vlast certainly tested their unanimity. The euphonious chordal writing which sets in prospect the rocky fortress of "Vysehrad" was a little fuzzy around the edges; the thickness of the texture, with distinct bias towards the winds, took a bit of getting used to.
Not even Norrington, master of the open, well-articulated sound, could do much about that, though he didn't concede to the weight of numbers when negotiating the Bohemian knees-up at the heart of "Vltava".
Then amidst the same Bohemian woods and fields we encountered the young Gustav Mahler and the magic descended. There's nothing quite like youth confronting youth in music. These youngsters could relate first hand to the wilful audacity of Mahler's First Symphony - the high risks he took, the bravado he displayed. They did too. If it hadn't been for the inveterate coughers the "sound of silence" at the outset might have stretched our ears still more. Because Norrington was stretching all the extremes, pushing the pace beyond recommended safety limits, highlighting the volatility, the rashness and youthful impetuosity of the score in the outer movements. And these kids were fearless in going the extra distance.
But it was in the third movement with its bleak minor-key rendition of "Frere Jacques" and cheap kosher café music that their precocity really came into its own. The characterisation was so knowing, the parody spot on, right down to the caustic clarinets and sleazy vibrato of the trumpet sound. Then again, at the dreamy heart of this movement, who would have credited the tender phrasing of the melody in muted violins. That was very grown up.
When the symphony's triumphant peroration arrived - with horns, trumpets, and trombones upstanding - it was not just exciting, it was moving - because it symbolised youthful endeavour, the will to succeed, and optimism for the future. Here's hoping.
Booking: 020-7589 8212; www.bbc.co.uk/proms. Prom 31 available online until Saturday