Hm, maybe tell that the after-school clubs, holiday clubs and childminder. In our area you can't get any cover for a secondary school child and DD turned 12 at the end of Y7.
Also, a child needs to be taught how to be alone and independent. You can't just say "oh, you are 12 so you can be alone suddenly".
It's a lot better to start slowly, letting them be alone for a bit, letting them walking alone to the shops or to friends.
DD went alone from her childminder to the Brownies at 6pm when DH was away on business, she walked along a street for 6 houses, we started at Summer term of Y5.
Then she walked from the car to her gymnastic club, again, just along a road in daylight.
At home we left her bit by bit, up to an hour so she felt ok during Summer term of Y6.
We talked a lot about various scenarios, the school did some role play lessons and I think all of DD's friends who didn't have younger siblings walked alone and had some time alone at home.