The scene is repeated twice daily in this affluent north London street, where half a dozen schools are situated within a few hundred yards of each other. Traffic grinds to a standstill in Fitzjohn's Avenue and surrounding residential streets, as thousands of children are delivered to and collected from their seats of learning.
The area is well-known as a school-run blackspot because of to its concentration of schools.There are rich pickings for hungry traffic wardens in the afternoon as parents park on yellow lines, in residents' bays and even on the pavement.
John Prescott, the Secretary of State for Transport, would have wept yesterday at the sight of a procession of Ford Galaxys, Land Rover Discoverys, and other gas-guzzlers drawing up outside Hampstead's over-subscribed schools and departing with one small uniformed figure in the back.
"It's a nightmare," said Sharan McTaggart, surveying the scene and fanning herself with a newspaper. Twice a day Ms McTaggart, a nanny, drives to and from Hackney, a 45-minute trip, to drop off and pick up her charges, Flo and Joe Beddle-Brill, aged four and seven respectively, from Devonshire House Preparatory School.
Ms McTaggart plans the school runs with military precision. Mornings she drops the children at the gate; afternoons she arrives at 2.30pm - an hour before the end of school - in order to secure a precious pay- and-display parking space.
Others adopt a riskier strategy. Petrit Riza, picking up his two children, was hovering yesterday on a double yellow line outside Fitzjohn's Primary, hazard lights flashing, engine idling for a swift getaway. Down the road, one optimistic mother had left her Mercedes parked illegally, with a notice displayed on the dashboard saying: "Parent collecting child from school."
There is no alternative to the school run, these parents and nannies claim. Public transport is too complicated and time-consuming, taxis too expensive, car pools too much of a headache to arrange.
Karen Falkner, who lives in Islington, where the poor quality of local schools was highlighted again this week, and who sends her three children to Devonshire House, said: "It's just easier by car."
But one cyclist, white-faced after nearly being hit by a Renault Espace, said: "Fitzjohn's Avenue is hell on earth."
The Espace driver was still behind the wheel examining her nails. Had she ever thought of sharing in a car pool? The woman did not reply, but her expression spoke volumes. It said: "This is my people carrier, and I'm not sharing it with anyone."