I agree with oesdog. I grew up in London, but walked alone to school from the age of 7 and when I went to high school at 11 I travelled across London on the tubes and buses, everyone did in those days.
I also well remember Ian Brady and Myrha Hindley who killed children not far from my grandma's house in Manchester.
We also disappeared for the day into the local park to play taking some sandwiches and a bottle of cold tea. We came home in time for our tea, although none of us had a watch, we knew it was 'home time' because people were returning home from work. Before tea, we ran errands for elderly or housebound neighbours which often involved trekking off to distant shops.
We were taught to be sensible from a young age, and how to use public transport safely. When I started high school my dad came with me once to show me the way and then I was on my own. I never got lost, or in any trouble. I do recall though that children under 7 were still in those days considered to be 'nursery age' and were much more supervised.
I have brought up my own children with as much freedom as was safe at the various stages in their development and had no problems. I deplore the fact that so many youngsters these days are being ferried around in cars by their over anxious parents, what is wrong with walking?
Children who are too protected will either grow up afraid of their own shadows, or unaware of potential hazards. Either way, they are in danger.