As the conductor motions the players to stand, one cry can be heard over the increasing applause - "Bravo, Colchester Youth Orchestra" - and indeed,there they are, unmistakably British, dressed in the familiar combination of white shirts and navy skirts or trousers. They have been performing the Vasa Symphony, specially written for them by their own director to celebrate the life of a 16th-century Swedish hero, later King Gustav I Vasa. This was the world premi re - and a huge success.
Young Essex musicians wowing Swedish audiences? Dudley Schools Orchestra from the West Midlands tours Australia - another great success. And next year, Brighton Symphony Orchestra plans to celebrate the millennium by performing in South Africa.
So may one then conclude that all is well with the state of young people's music in Britain - and in Britain's musical offering to the world?
"Well, no, not quite," warns Nigel Hildreth, teacher at The Sixth Form College, Colchester, director of the Colchester Youth Orchestra and composer of the Vasa Symphony. "Twenty years of cut-backs in musical provision have had a catastrophic effect. But there are oases, small areas of excellence."
The music department of his sixth-form college could be described as one of them. Nigel Hildreth's enthusiasm is infectious and his standing is high. Damon Albarn and Graham Coxon, members of the rock band Blur, are former pupils, who have returned to the college to run workshops.
Nigel Hildreth's wider reputation rests on his deep commitment to the cause of young people's music. He started the Colchester Youth Orchestra from scratch in 1981, when it was called the Colne Valley Youth Orchestra, and ran it for the first six years with only the help of his wife and a couple of friends. With an ambitious programme of concerts (many of them directed at younger children), foreign tours and the participation of local composers, its reputation grew. It now has a junior training orchestra, and the main orchestra has become a recruiting ground for the larger county orchestras.
But it's been a hard slog, says Nigel Hildreth, who steered clear of local authority involvement, given their unpredictability as funding agencies while music policy shifts and stutters in the cold wind of retrenchment. He keeps the orchestra afloat and independent, he says grimly, "by running the whole thing very tight, exploiting the goodwill of parents and finding sponsorship where we can".
Andrew Sherwood, the charismatic leader and musical director of the Brighton Youth Orchestra, is in a far more secure position, for the BYO (billed as the oldest independent youth orchestra in Europe) can depend on vigorous parental and local support in their well-heeled part of southern England. It also has a string of successes to its name - it has twice been the winner of the best youth symphony orchestra award in Britain, it has performed a live broadcast on Classic FM, worked with Glyndebourne Opera and South East Dance Agency, and has received coaching from the London Symphony Orchestra - all of which makes sponsors more approachable.
Sherwood, though, is not complacent about the state of youth music. "I'm very aware there is a crisis in many areas, but I'm also convinced the tradition of youth orchestra - very strong in this country - is the biggest single thing that keeps music going. There is always a knock-on effect of excellence, and it's our task to provide access to it."
In the West Midlands, cellist Keith Horsfall has a foot in both camps of youth music - youth orchestras and schools. He is an executive member of the National Association of Youth Orchestras, he conducts the Dudley Schools Symphony Orchestra (which last year toured Australia) and works as deputy head of Dudley Music Services, which is dedicated to bringing instrumental music playing back into schools.
"Youth orchestras are at the apex, the top of the league, like Manchester United in football," he says. "But if we ignore music in schools, we're building on sand; everything will collapse."
Dudley's initiatives have already produced some heartening results. Last year, Sledmere Primary School started up an orchestra of 25 to 30 members. In response, the neighbouring Northfield Road Primary persuaded its governors to hand over Pounds 10,000 for musical instruments and tuition, and now has an orchestra of 70 players. Knock-on effects of excellence? Could the tide be turning?
Bursaries and grants, subsidies and sponsorships, all now play a vital part in the music business. Sainsbury's, for example, has recently stepped in as a major sponsor. Its Youth Orchestra Series was launched in 1996, directed at helping youth orchestras from country, metropolitan or unitary authorities. This year its Arts Sponsorship Programme has been extended to include concert awards, the chance for six orchestras to record with Classic FM, and funds for specialised instrumental tuition. All agree that this support, both practical and inspirational, will make a difference. In the meantime, dedicated teachers, composers and musical directors continue to create oases, pockets of excellence, where young people make music together.
It is unquestionably important. In Andrew Sherwood's words: "Playing great music changes young people's lives. It's a magic they will never forget. "
YOUTH ORCHESTRAS OF EXCELLENCE
* Brighton Youth Orchestra Contact: Natasha Atthill, tel: 01273 643450 Entry requirements: Grade 7 standard for first orchestra; Grade 4 for second orchestra. Both by audition. Junior Orchestra: Grades 2-3, no audition Age: 6-21 Membership fee: #163;75, less for siblings * Dudley Schools Symphony Orchestra Contact: Keith Horsfall, tel: 01384 813868 Entry requirements: strings, Grade 6; wood-wind and brass, Grade 8 Age: 13-19. No fee * Colchester Youth Orchestra Contact: Mrs Bazley-White, tel: 01206 337 334 Entry requirements: for main orchestra, Grade 5; woodwind, Grade 6 Age: 11-18 Membership fee: #163;40 a year, less for siblings
Nigel Hildreth can be contacted at The Sixth Form College, Colchester. Tel: 01206 500 700For information on Sainsbury's Youth Orchestra Series, tel: 0171 695 7851