another 'what would you have done?'

Well done for trying to help the poor girl - it's so easy to pass on by and do nothing.

Yes I would have done the same. The police have the power to ask questions and keep her safe till they get the answers.

Thanks to all - I'm still thinking about her, just round the corner from us.
As some of you say, could be a problem of mental illness.

You did the right thing x

The police can indeed do a lot, and in my experience, are usually very kind and helpful. It is true that some people undergoing a mental breakdown (also a possibility) are kept inappropriately in police cells, but that is the fault of the system in general / NHS resources.
I have also found that the police are good at mobilising resources, so I hope this poor girl got some help.

So sad....I don't know what the answer is, but I think the Police will eventually find her and sort something out for her, She certainly needs help. I feel really sad...I have a grand daughter the same age.

The police can do a lot.

You'll never know what it was about, could be anything. I would have done the same, reported to the police in some way, just in case.

You don’t know the previous circumstances and the police can help her, if only to keep her safe whilst they decide what to do. You were trying to help so well done for not just ignoring her but the police are good I think