Son being bullied

[StressedToSickness]

My son is being bullied by another child, the bully is a little bit younger so my son can't even defend himself otherwise he gets the blame. I've tried talking to the other child multiple times, I've told them both to stay away from each other and I've even tried talking to the other boys mum but she did nothing. My son is by no means perfect and he has retaliated and probably antognised to some extent but this child has hit my son with a metal bar, and a baseball bat, he has pulled on his hair and ears and tried to choke him. I'm not sure what else I can do. I have thought about phoning the police as a last resort, but I'm worried that could make it worse, I've spoke with them before and because they are young children they don't seem to care/there isn't a lot they can do. It is happening nearly every day and is stressing me out to the point where I feel incredibly unwell, I feel so bad for my son but I don't know what else I can do :(

Thats what I keep telling him, he says leaves when he can but when the other kid is putting his arm round his neck and dragging him to the floor he has to push back. I have his friends over when I can but they're a very active lot and don't really like spending a lot of time indoors, my garden is ridiculously tiny so they can't even play out there.

He needs to avoid this place unless you can go with him. (Though would’ve thought that a bit embarrassing for a child his age.) He needs to stay away from this kid. Should they encounter each other he needs to get away. Not stay until the kid has him in a head lock. Is this child behaving like this to any other children or just yours?

He does it to a few others yes, I've kept him away since but he even bumps into him walking home from school, the other boy keeps calling him things and saying awful stuff about me but at least it's nothing physical at least.