Asked to explain what an unnamed symphony is about, a composer might reasonably answer “it’s about itself”. Exactly how our response changes when a title or context is given is a hefty question, but one that fascinates. When the associations are as potent as those with Sally Beamish’s Viola Concerto No 3, “Under the Wing of the Rock”, we are engaged from the start.

This persuasive 2006 work was the centrepiece of the BBC Symphony Orchestra’s Echoes of Scotland concert, directed by their talented young associate conductor, Alpesh Chauhan. It also featured Mendelssohn’s “Scottish” Symphony No 3 and Peter Maxwell Davies’s charmingly bibulous An Orkney Wedding With Sunrise.

Beamish’s title comes from a Gaelic song, Lullaby of the Snow, sung by a mother to her child as they flee the massacre of Glencoe. A soldier is dispatched to kill them. Unable to commit the deed, he shelters them and kills a wolf instead, showing his officer the blood on his sword. How does such a complex tale express itself in abstract music? More simply and directly than you may think.

Beamish (b1956), herself a viola player, has a rigorously honed creative voice. Her music is generous and evocative. Originally written for the Scottish Ensemble and Lawrence Power, the soloist here was the equally starry violist Timothy Ridout. The concerto opens with viola alone, at first in short sighs and gasps, then expanding into a lyrical lament, with the strings of the BBCSO joining with hushed, shimmering chords.

The mood darkens, with a rapid pizzicato figure for viola, the orchestra choppy and jittering until panic disintegrates into a quiet dialogue between soloist and front-desk strings. All reunite, the soloist playing pianissimo, to the ethereal end. Ridout plays a viola (c1565-75) by Peregrino di Zanetto, an important Italian maker, but he’s that rare kind of musician who could play a cardboard box and make it sing.