The BBC Symphony Chorus returns a favour when it performs Walton’s Belshazzar’s Feast with the BBC National Chorus of Wales at the opening night of the Proms on 17 July. Last time, nine years ago, it was the Welsh who invited the English. In both countries, choral singing is thriving as never before. The quality of the voices and numbers involved are at an all-time high. We are undoubtedly living through a golden age of singing.Choirs rarely performed at the Proms in the early years when the concerts were primarily orchestral with soloists. Beethoven’s Choral Symphony was performed without the final movement until the 1920s. Choirs existed, but not in such profusion as now. What became the BBC Symphony Chorus started out as the National Chorus in 1928, two years before t