Tallis’s 40-part motet Spem in alium stands as one of the most astonishing achievements of the human spirit, unrivalled in the a cappella idiom in its complexity. The very size and scope of it calls for forces which enable us to programme some other substantial masterpieces we cannot normally perform: Sheppard’s 6-voice Missa Cantate; and Robert White’s glorious Magnificat, replete with a triple gimell.

But perhaps the pièce de résistance in this context is John Sutton’s 7-voice Salve Regina from the Eton Choirbook. It may have fewer parts than Spem, but it is just as much of a challenge to sing.