IMHO fine, no risk of mains voltage unless the charger/power supply is of dubious origin.

Fine with the phone OEM charger.

Leads can be an issue, but not from a voltage standpoint, only 5V dc.

Overheating and fire possibly with cheap leads, but, less likely to be dangerous than the power supply.

That is unless you are looking at the Samsung Galaxy Note7, in which case, ban the whole phone from site!

Additionally the cost of supplying electricity goes to the college and it amounts to lots and lots of £ over a year; money which then effects the H&S & which could go to better causes - And with all due respect students are the last people that will take care of their kit

I would go with WatsonD on this and staff should only charge their kit at work if it is used for work activities e.g. for the good of the college

The main thing you need to watch out for as been said, is cheap imported chargers which do have a habit of catching fire, The fact that people leave their phones which could pose a risk of theft, and then theirs the other issue, what happens if the phone gets damaged, a surge, or spike in the supply may damage the phone, or its contents.

Perhaps the school or Collage could invest in Charging stations, perhaps coin operated which would see a dramatic fall in the amount of people trying to charge up there phones for free, but on the other hand the school will have the correct equiment to be able to offer Mobile Charging

We use these on building sites, which are lockers that have a socket inside, People can just plug their phone in, Pay a £1 and lock it up, securely

Thanks everyone for replying. Clearly this is one of those situations where you are damned if you do and damned if you don't. With the increased use of IT in classrooms encouraged and some colleges actively encouraging learners to bring in their own tablets etc to enhance learning., I think this might roll on and on.

The original enquirer, has encountered positive and negative approaches in his journey around various colleges and it seems there is no hard and fast guidance.  I think good old common sense must prevail until such time as we are advised otherwise. 

Many thanks, great to have a network of like minded professionals to refer to.

Keep up the good work.

My issue is that the students use the right chargers. I had an Italian student who managed to force a Italian two pin plug into a UK floor socket in the library to recharge their phone. They got it to work! The charger plug pins were damaged and the socket need replacing but it demonstrates what you can achieve by applying the right levels of stupidity and stubbornness.