"It's snowing," the excited buzz goes around the classroom. It isn't that cheap, sleety, powdery sort either - the one that masquerades as snow. This is the real thing - the kind that makes crystals under the microscope, the kind that carpets the ground, the roofs and the branches of trees. The magical kind that muffles sounds and creaks underfoot and makes everyone think of Christmas and winter and woolly hats and tobogganing and toast beside the fire. The kind we hardly ever see in London.
It becomes a day when the normal routines are swept aside. One teacher takes her class to the far end of the playground. The snow lies there, pristine, white and untouched. She lets the children make footprints. She lets them make their mark.
Sandline, who came to this country from Rwanda after her parents were murdered, gazes into the sky, allowing flakes to fall and dissolve on her tongue. Others run on the field, rolling the snow into large balls making embryonic snowmen. Several throw snowballs at each other. Even the staff join in.
A few months ago, I was with a headteacher who was recalling a foggy day, a real pea-souper, and commenting that not one teacher in her school had taken their class to explore the weather phenomenon. They'd missed the opportunity in favour of the usual diet of class-based literacy and numeracy, partly through fear they would fall behind in completing the plans and partly (and this is more worrying) that it never occurred to them to break the routine and follow their instincts. It was far too adventurous.
Yet in many respects, this is the very stuff of life. It's put there for us to explore. Once experienced, never forgotten. Allowing children to immerse themselves in fog or snow enables them to connect with poetry such as Sandburg's "fog coming on little cat feet".
Children are increasingly insulated from the wonder of direct experience in this world of tests and tasks and health and safety guidelines. Large snowflakes floating down from the sky are downright magical. The children may get a bit wet, their fingers might tingle with cold, their toes nip with frost. They might even slip and hurt themselves or get a snowball in the neck, but they'll have a good time, too. "This is the best day I've ever had in school," said one child after they had trooped back into the classroom.
One of my colleagues even took our overseas teacher, who had never seen or touched snow, to a nearby park so they could slide down a slope on a plastic sack. Snow brings out the child in us all.
The following day, as I sat in an overheated and stuffy room, listening to a Qualifications and Curriculum Authority representative drone on about changes to the key stage 1 and 2 tests, it occurred to me that we have got it all wrong. We are so caught up in the constant drive to make infants like juniors (there are marks available in the key stage 1 writing for using commas to delineate clauses) and juniors like mini-secondary pupils, that childhood becomes irrelevant in the Orwellian world of rigour and standards.
I have heard of many schools where the children were kept inside the day it snowed. Why? For fear they might enjoy themselves?
Like the soldiers who swapped their chocolate and cigarettes across the trenches on Christmas Day in the First World War, for one day in our school the normal curriculum went out of the window. The world was a place of wonder and children became children again.
Bob Fletcher is head of Hobbayne primary school, London borough of Ealing