I would normally say 'keep your nose out', but then if we all did that, possible child abuse may go unnoticed.
It may just be that the child has hit the 'terrible two's' and the mother cannot cope. In which case, she may need some help and support. Obviously there may be something more sinister going on, but you shouldn't really jump to conclusions.
Anyway, I think you should contact your local council, ask to speak to social services and say you have concerns over a child's welfare.
They will take as much detail as they can with you, over the phone, and will then send someone round to 'investigate'.
It'll be pretty clear (I would hope!) if the child is being mistreated, and I would imagine it would also be pretty clear if the child is well cared for (fed, clothed, clean etc) but perhaps the mother is struggling.
Either way, I think you should call them.
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