Simon Holt's hugely impressive new violin concerto, a BBC commission premiered by Viviane Hager with the BBC Symphony Orchestra and conducted by Jonathan Nott, bears little relation to conventional ideas of what a violin concerto should be. In his recent works, Holt has explored the possibilities of building large-scale forms from a sequence of miniaturised movements, and the new concerto, Witness to a Snow Miracle, continues that trend, consisting of seven movements adding up to just over 20 minutes of music.

As the title suggests, the piece is programmatic - though Holt leaves the precise perspective of that programme to the audience's choice. It is based upon the life of the fourth-century Christian martyr St Eulalia, who was tortured and killed by the Romans in Spain for refusing to worship their gods. She was burned and, when a blanket of snow fell on her ashes, she was declared a saint. The solo violin, says Holt, is "possibly Eulalia herself, or a witness to her torments and martyrdom (or are we as listeners witnesses to the proceedings?)".

The titles of the individual movements - from the opening violin solo depicting Eulalia herself, through The Tearing, the Burning, to Torments and Halo - seem to plot her path towards sainthood. But throughout the work, both the solo and orchestral writing are so vivid that their precise correlation with the programme seems to matter less and less, and the whole adds up to far more than the sum of the individual parts. Holt sets the violin against a strangely skewed orchestra lineup that includes two piccolos, two harps, a piano and celesta, but no trumpets. Used sparingly, it conjures a series of haunting, vivid images and creates a delicate, bright sound-world against which the violin's nervous, hyperactive lines stand out sharply. In that one respect at least Witness to a Snow Miracle is a conventional concerto, for the solo violin part is fearsomely difficult; Hager had mastered it exceptionally well.