"Why," she asked, "Do so many people pick up their children from school? In Norway most children walk to their school."
And so they used to in Britain. Mayer Hillman, editor of Children, transport and the quality of life, found in a survey of children that in 1990 only 9 per cent of seven- to eight-year olds walked to school on their own. The proportion is highest for primary-school pupils.
Next week, the Environmental Transport Association, working with a number of local authorities, is organising a Walk to School Week as part of its Green Transport Week activities. The campaign seeks to encourage children and parents to return to thinking of walking as the main way of getting to school. The benefits are obvious. Parents delivering children to school form a significant proportion of car traffic, contributing to pollution and causing danger outside schools by parking on the zigzags, or even, as happens outside my daughter's primary school, double parking.
At least 16 authorities in London and many outside are involved in walking to school week. At this stage, the idea is to raise awareness about the issues, as much as actually changing people's travel patterns. Activities include surveys and questionnaires on travel habits and, in Waltham Forest, demonstrating a machine that monitors the level of pollutants, such as benzene, to which children are exposed. Safe routes will be identified on maps and children will be asked to undertake surveys to estimate vehicle speeds and projects on the costs of the car.
The campaigners face an uphill task, since the two main reasons for the change are fundamentally embedded in late 20th-century society. There is a widespread - and, according to Mayer Hillman, a complete irrational - fear of abduction by paedophiles or other sexual perverts. Dr Hillman, who has studied Home Office figures on abductions, reckons that the number of cases annually is so small as to make the risk infinitesimal compared with all kinds of other children's activities, such as using climbing frames or even playing football: "If you really want to prevent child sex abuse, you keep children away from their parents, not off the streets."
He feels that British parents' disproportionate fear of paedophiles, which does not appear to be shared by our European neighbours, is the result of the attitude of the press: "The tabloids so blow up the very occasional cases, that they have managed to create a climate of fear." There is no evidence that such cases have increased.
The second reason is totally rational - concern about crossing roads and road safety. In an effort to overcome this problem, a number of councils have started "safer routes to school" schemes, whereby children are directed to take specific routes to school on which special crossings have been created. But Dr Hillman is critical of this approach, as he feels it is unrealistic and segregates children: "All neighbourhood streets should be accessible to children, not just a few." He believes that raising junctions to pavement level and giving pedestrians priority at those junctions throughout a road network would make an area safe for children, not only to go to school but to visit their friends. And the speed limits should be reduced to 20mph, as in many parts of Europe.
There are other reasons that children no longer walk to school. Many more people, even some older pupils, now have cars. Many more women go out to work and may drop their children on the way. And with opted-out schools having much bigger catchment areas than the conventional local authority ones, the journey to school may be difficult by any other means than car.
To allay fears about children walking on their own, the campaigners are saying that children should be accompanied, either by parents or by other children. But, ultimately, Walk to School Week raises a much more fundamental issue about the way that our society treats its children. Dr Hillman feels that the growth of the motor car has taken away children's right to mobility and in effect forced them into "house arrest".
"There is huge damage - injury even - being done to children by not allowing them their freedom," he says. "It is psychological and physical. People say, 'I will not risk allowing my child out on the streets.' But the injury caused to children by not letting them go around is much greater because lack of exercise in childhood lays down a pattern for life."
The Environmental Transport Association can be contacted at The Old Post House, Heath Road, Weybridge KT13 8RS.