Not in the UK, but I guess it was a bit similar, when I was 7 or 8 years old I had the key to my house, would go shopping nearby for groceries etc, and often would walk about 1 mile through the city center to meet with my mother at her job. My mother often worked nights and I would stay home alone, and knew the "protocols" on how to act in some scenarios (i.e., strangers knocking on the door, emergencies, etc.)Bloody hell!
My brother was born 12 years later than me and was raised in a radically different way. He was taken to and picked up from school until he was about 12, even though it was a 5 minute walk. He never stayed home alone, let alone at night, and probably didn't wander alone on the city until 14 or 15.
My ex-daughter-in-law is 15 and never left the house alone.
Things changed very quickly. I don't think the cities became more dangerous, people just are so much more careful these days.