Local muggings - should I let my son go around on his own?

[QuestingParent]

There’s been a number of muggings in our area and I’m wondering how to respond for our 14 year old son - should we insist he’s escorted by an adult? Always walk in a group?

He needs to walk to/from school, to local music lessons, shops and visit friends.

The muggings have been carried out by older youths going for younger kids, in local streets after school and the local park. They demand phones and cash, and in a few cases there has been punching. We're in a quiet residential part of south London.
Any advice?

Ideally he could walk as a group. Could he cycle for some of the trips ? (RTC risk is probably more of a risk than being mugged though). I’d avoid the hotspots if you know which streets are being targeted.