This is an imaginative programme of settings of Marian texts by Nordic composers, including Anonymous (the Ave maris stella from the Piae cantiones collection). The standard is set by a fine rendition of Rautavaara’s Canticum Mariae virginis from 1978, a work I am always surprised to see so infrequently in concerts and recordings. It’s not easy but it has beautifully lush choral textures and what I can only describe as a cumulative sense of wonder that more than justify the effort, though the Key Ensemble sound as though they have the piece in their blood.

Britta Byström’s mysterious, floating Lux aeterna may seem not actually to fit the programme thematically but it does in atmosphere, suggesting the Northern Lights, and once again seems to have found the perfect interpreters in the Key Ensemble. Mikko Heiniö’s rhythmically and harmonically colourful Maria Suite, a Key Ensemble commission, is quite different, traversing languages and cultures to provide five different Marian visions, beginning with a spiritual and ending with the Slavonic ‘Bogoroditse Devo’, using the Valamo chant as a cantus firmus. Hillborg’s muoaeyiyaoum is another ‘lights’ piece – the booklet-notes actually describe it, appropriately, as a ‘screen saver’ – of tremendous intensity and beauty. Nystedt’s Stabat mater is described as a ‘programmatic concerto for cello and mixed choir’, though it gets through the lengthy text in only just over 15 minutes.

Bror Samuelson’s lush Ave maris stella brings this adventurous and magnificently sung programme full circle. This is a choir to watch.