MARK CAZALET is a well-established figure in today’s ecclesiastical art world. He has completed many church commissions. Typical of this London-based artist, born in 1964, are his urban scenes, such as the appropriately busy Carnival Triptych for the Notting Hill church St Clement’s, Notting Dale, or his 2001 reredos for the Fraser Chapel in Manchester Cathedral.

More familiar, probably, to most visitors to his exhibition in St Edmundsbury Cathedral would be the calmer and more agrarian vision in his Tree of Life (2003), on oak panels that fill in a blocked-up window at Chelmsford Cathedral.

For Bury St Edmunds, he took up a residency last February. Since then, 153 volunteers — a symbolic number, from the miraculous draught of fishes (John 21.1-14) — have sat for half an hour’s silent meditation while Cazalet painted them in two colours, on a background colour of their choice. One sitter’s session was interrupted; so he was painted twice.

Each painting was completed and hung at head height in the cathedral on the day of the sitting. The cumulative installation references the tiered hierarchies of figures in the iconography of Orthodox churches.

It is an achievement on the part of both artist and sitters. Every portrait-painter must help his subject to achieve stillness; this required more. The artist was assisted by the support of the staff and the space that was made available to him. The north-transept gallery proved an oasis of serenity, he says. “The business of the world seems diminished, filtered cathedral sounds become almost sub-aquatic. The tall clear glazed windows pervade a soft northerly light that gently reflects from plain limewash walls.”

Each session began with an introduction to silent meditation, and a mantra was used. “I used the analogy of Heidegger’s Lichtung: life seen as a meandering pathway through a dense wood with tangled roots and a heavy canopy, punctuated by occasional sunlit glades. . . The walker is filled with warmth, sensing an immensity of light, space and potentiality. Our sessions aimed to enable such epiphanies.”

Sitters experienced feelings such as consolation, joy, or the safety to face difficult experiences or grief. They have come back repeatedly to view the portraits. The artist describes the months of shared silence as “a marvellous and revelatory process, which has changed me, and, I hope, many of the participants”.

“Silent Colour Meditation: A Great Cloud of Witnesses” runs until 4 February, when it closes with a day conference on “Intimacy and Ultimacy” (phone 01284 748722 or email DeansEA@stedscathedral.org to book, before 27 January). www.markcazalet.co.uk