When you say “child” what age are we talking?
I really dont see any need for children to have phones. Parents always say its so they can contact them in an emergency but this doesnt make sense to me. If the child is at school. Phone the school. If they are at a friends place surely you have the parents phone number and can call there. Children should noyt have phones, there is no need and this removes this kind of worry.

Teens with phones should onbly have phones if you trust them to be responsible and therefore you do not invade theri privacy unless you have a strong indication of wrong doing.

I would say it depends on the age of the kids. I would have been pretty furious as a teen if my parents were trying to go through my phone. I wasn’t a rebellious kid, it’s just a time where privacy is Important. I would instead try to foster open communication and a no judgement zone between you

In addition to my comment below; it is a good idea to get resources from school and other sources about the use of mobile phones and about all topics and behaviour related to the use of phones. It is always a good idea to sit down and discuss all things related to kids and to listen to any of their concerns.

I believe kids messenger allows you to do this and I am sure there are other apps out there that can as well. My daughter is too young and doesn’t have a phone yet but being able to ensure she isn’t being bullied or being a bullied is a high priority for me as kids sometimes don’t know how to bring up subjects like this.

We have a teenage son and we have only ever checked his messages and chat apps when his behaviour had a massive change, we would explain why we wanted to look and if he had something to hide that he had been doing that he shouldn’t have been that it was better to tell us before we found it. We trust our child and yes they are going to do silly things but as long as he is comfortable in coming to us if something happened then we don’t need to regularly check his phone.

We never did, our kids we always welcome to share something with us what was on their heart and they did. Even now our eldest two kids are 21 and 20 yrs old and they come regularly to show and share a text they received. Our third child (we have her under a legal guardianship and she has a complex profile) on the other hand we blocked from many access in the past

We have always had the rule of phones being similar to diaries and journals. They are not for the eyes of others. Privacy is of course so important and trust and respect has be given for children to grow into adults that trust and respect themselves and others. Of course; we delayed phones being used until the children were of an age of being able to understand being responsible and honest.

This has got to be one of the biggest questions with teens. Do you trust the child? Has their behaviour suddenly changed and you suspect something has happened? Try and have an open conversation with them. If you go through their phone they are likely to pull away from you.
Hold on and trust the way you have raised them. Be there for them if things go wrong x

It really depends on the child and if they are giving you any reason to doubt them. I think you should let them have their privacy unless you start to see signs of anything that you need to monitor. For example, my daughter is 13 and on the spectrum and occasionally she may overdo it on the messaging, then we may check what she has been writing. For the most part, however, we do give her privacy and sometimes she even wants to share what she has been saying to friends.