I am a teacher myself and I don’t know.
One of my groups are writing a speech about why they should be allowed to bring their phones to school, and I was explaining in my last school phones were confiscated until the end of the week for a first offence and end of the term for a second one.
A few of them asked if that was allowed and I guess it must be as I know of a few schools with this policy or similar. I must admit I don’t know where the legal position is if the phone belongs to the parent though. Wondering if anyone here knows so I can tell them next time I see them 