As I walked across Hyde Park to the Royal Albert Hall on Sunday afternoon, there was a great roar of delight from inside the park’s giant Olympic video screen enclosure. Andy Murray was on his way to Olympic gold.

The triumphant sound proved to be the ideal curtain-raiser to the afternoon’s very British BBC Prom. Ben Parry’s Flame, receiving its first Proms performance, is prefaced with the words: “Thousands of candles can be lit from a single candle, and the life of the candle will not be shortened.” What better description could there be of the Olympic Torch Relay? Sung by the BBC Singers and the National Youth Choir of Great Britain, the ethereal music swelled in a straight line from a whisper-quiet beginning to a mighty climax. Most effective.

The Singers and the NYC were then joined by the Bach Choir, the Great Baddow High School Signing Choir, and children’s choirs from three London boroughs — a total of 550 singers in all: no wonder Catherine Bott, introducing the concert for Radio 3 listeners from the stage, described the afternoon’s conductor, David Hill, as “totally unflappable”.

Stacked right up high on both sides of the Albert Hall organ, they gave the world premiere of The Angry Planet by Oxfordshire-based composer Bob Chilcott, using words by poet Charles Bennett. The writing develops in three interweaving strands — first, poems linked to specific hours of the day; second, lines in celebration of the plant kingdom (concentrating, to the horror of gardeners no doubt, on the proud heritage of weeds); and, thirdly, four dark songs focusing on human exploitation of the planet.

Chilcott used different sections of his vast choral force to point up these different strands. The BBC Singers, for instance, can sound very staccato and harsh-voiced, so they took the part of the human aggressors: “Chainsaws whine and howl as the forest dies.” In complete contrast, the massed ranks of eight- to ten-year-olds in the children’s choirs got highly singable tunes and lovely lines like “We’re printing the form of our faces on the meadow, peppermint freckles smelling of fresh air and clear skies”. Chilcott loves to draw different textures and harmonies from different types of human voices, and he eagerly exploits every opportunity to do so in this new work. Conductor Hill and his forces did him proud — the choirs had obviously been expertly rehearsed, and brought to concert readiness at just the right moment.