An appearance by the world’s first national youth orchestra should have attracted a huge response from supporters of young musicians. Not so.

On Friday we witnessed a Town Hall less than half full for a concert that, with better promotion and at a different time of year, ought to have filled the place. Make no mistake: as well as being the oldest (it was founded in 1945) the National Youth Orchestra of Wales is probably one of the best youth orchestras in the world. These musicians aged 13 to 21 have maturity and confidence well beyond their years. Their finely co-ordinated playing is impressively secure and polished.

In Owain Arwel Hughes they have an avuncular music director whose conducting is encouragingly clear and helpful, a quality much appreciated by players with limited experience.

The programme was designed to display orchestral strengths. William Mathias’s attractive and deliciously scored Celtic Dances were played extremely well, with deftly pointed woodwind, often surprisingly delicate brass, and a vibrant gloss to the strings. Britten’s Young Person’s Guide similarly showed off every department, often sounding like two orchestras (as is the youth orchestra norm wind and brass in the NYOW are freely doubled), the individual variations full of lively detail and culminating in an excitingly controlled, and accurate, fugue.

However, the real jewel of the evening was Vaughan Williams’ A London Symphony, lovingly and glowingly delivered in an emotionally charged reading that owed as much to the commitment of its young executants as it did to Hughes’ well-conceived reading. Superbly paced and beautifully sonorous, it was intensely moving and really quite marvellous.