One January evening, not long after sunset, my daughter spots the first flutters of London snow, caught in the orange beam of a street lamp. Soon it’s dumping down. We watch an altered landscape emerge. Trees and shrubs transform into abstract statues, their edges softened by an icy shroud. At the open door, the cat puts one paw in the snow, holds it up and licks it. She marks out a trail of perfectly formed paw prints and rushes back inside.

Our house overlooks a small marina and in this confined space the surface water has frozen, the houseboats with their black hulls and strings of coloured lights are locked in ice, abandoned by owners seeking warmth. The scene is beautiful, but something is amiss. An almost indiscernible shimmer appears, disrupting my vision. Translucent lines appear before my eyes, a tiny mirror-ball materialises. It grows and changes shape. A delicate rainbow forms along its rim.