IN July, all roads lead to Strathallan. And not just for this weekend's second year in the locale for Scotland's T in the Park pop, rock and dance music event. Probably rather less raucously – but possibly not – over the next three weeks or so there will be an extraordinary mobilisation of Scotland’s musical talent as 319 of the best young musicians in the country are bussed to Strathallan School in Perthshire to begin intensive training and coaching in a series of residential courses. These will culminate in a succession of flagship display concerts ranging in locations from Sabhal Mor Ostaig on Skye to the RSNO Centre in Glasgow, from Greyfriars Kirk in Edinburgh to Perth Concert Hall, from Wiltshire Music Centre in Bradford-upon-Avon to Glasgow City Hall, and from St David’s Hall in Cardiff to the Royal Albert Hall in London.

This, you might gather, is the build-up to the launch of the annual summer touring season by the National Youth Orchestra of Scotland. And before I go one step further, let’s just clarify exactly what sort of organisation NYOS now is, because I have been asked that many times recently. It is by no means a daft question, because NYOS has developed into a rather complex, multi-layered musical operation.

The National Youth Orchestra of Scotland is an umbrella group, or parent group, if you like. Within its charge are three symphony orchestras, arranged, though not too rigidly, according to an age grouping. The NYOS Junior Orchestra for the summer tour has 95 musicians, and they are aged eight and over (don’t be teased by the age: they can play way beyond their years.) The NYOS Senior Orchestra, with 85 musicians in its ranks is a hefty outfit, aged 13 and over, with a gathering sense of power and command: they are getting to know their way around the musical block, as it were. And then, at the top of the age pyramid, are the big yins, the NYOS Symphony Orchestra – aka Big NYOS – with 111 musicians aged 25 and under, who, on their night, you could put on any stage in the world; and they’ll jolly well have to be on their night this year when they take the stage for a prestige concert at the Royal Albert Hall in London as part of the BBC Proms.

But NYOS is not just the three classical orchestras. There is also the NYOS Jazz Orchestra, with 22 instrumentalists and six vocalists. They’ll be in Glasgow next Sunday night (17th) in the RSNO Centre at 8pm on the second leg of their summer tour. And then there is NYOS Futures, a graduate group, so to speak, who specialise in tough contemporary music. They’ll hook up with senior members of both NYOS jazz and classical orchestras for a new Duke Ellington project in the autumn. And there is NYOS Camerata, a virtuoso chamber ensemble which will collaborate with a Dutch specialist contemporary ensemble under the direction of Will Conway of the Hebrides Ensemble for performances in August of Wagner’s Siegfried Idyll and Schoenberg’s Chamber Symphony No 1 (what a dynamite programme),

There’s a lot of high pressure stuff here. But everywhere you look in the NYOS summer programme there is high pressure; that’s the name of the game. On Friday August 5, when the NYOS Jazz Orchestra takes the Royal Albert Hall late-night stage for its 10.15 Prom, they’re under pressure. Performances have to be top-drawer: jazz aficionados are incredibly uncompromising, fussy and critical. When Ilan Volkov takes the NYOS Symphony Orchestra into its Albert Hall Prom concert at 3.45pm on August 7, the musicians will be totally under a ruthless spotlight. There will be a new piece by Helen Grime to play (one of two written by the Scottish composer – the other will be played by the BBC SSO in one of its own Prom concerts), and new music can never be taken for granted. On top of all that, in the NYOS Symphony Orchestra’s performance of Tchaikovsky’s relatively little-known Second Piano Concerto, with Pavel Kolesnikov as soloist, there will be a very intense spotlight on NYOS leader and first violinist Ye Ye Xu and NYOS principal cellist Findlay Spence who, with soloist Kolesnikov, will form a piano trio of soloists in the unusual and much-discussed second movement.

Nobody escapes: there is not a pressure-free concert in the summer season. Conductor Holly Mathieson (recently appointed the assistant conductor of the RSNO) has to get NYOS Juniors through musical tongue-twisters from Khachaturian’s Spartacus to Copland’s Hoedown. James Lowe has to steer the NYOS Seniors through the rhythmic minefields of Bernstein’s West Side Story Dances and a new work by Oliver Searle. I can’t wait: I’m on the edge of my seat already.

For full concert details, venues, times, tickets: visit www.nyos.co.uk