What is the youngest to leave a child on their own ?

[crystaltips]

My DS is 10 and as yet I have not left him alone in the house for 5 minutes, let alone a couple of hours .... However some of my mates leave their kids ( aged 10 ) for about an hour whilst they collect other kids from clubs etc.
I was just wondering what you thought about leaving kids "Home ALone".
Instructions like, don't answer the phone / door ... and here's my mobile number in case of an emergency ....
It's not just that that worries me ... but what if I get into a car accident and cant get back to the house ... the mind boggles.
It's all a part of growing up and cutting the apron strings ... but when so I start to let go ... ?

I could've written Fairymum's post - both my parents worked full-time from when I was 7 years old. I had a key to the house, let myself in, fixed myself a snack, and watched tv and did my homework everyday. I also knew a lot of other kids in a similar situation. I don't think I'd leave my DD alone at 7 though - different times, etc. . .

If I leave a responsible fourteen year old home for three days with a responsible adult checking in on him throughout this time. (Bearing in mind this adult lives in the same building and is a relitive.) In the eyes of the law, is this illegal?

11 year old dd left alone in house on occasion, generally if she doesn't want to nip to shops with me and her brothers ( 1/2 hour max) - once when she was ten, she's been up all night being sick and i had to take her brothers to school. she's told to never answer door or home phone (unless it's my secret ring of two rings, then hang up, then ring again..) .