So I went out the side door, waited for him to turn the corner, then I pounced.
Loud Sho Voice "'Scuse me, you need to keep the volume down and you need to switch that phone off in the library."
Bloke looks at me, continues talking, I realise he's eleventy billion feet tall and stand my ground.
(thank you all so much for your comments to my flocked post yesterday - I will be replying to each and every one of you in person)
eta bloody hell! What is it with people today? Walking back through from the other department I encounter another student doing the exact same thing! So he got the same treatment. (And of course the fact that twice so far today I've had Sam Winchester telling the world that his daddy shot their daddy in the head through the medium of my phone* has no bearing on this...)
* my new awesome phone (still the same number, just a new handset) wot I got given at the weekend by wenchpixie 'cause mine is slowly dying. (it's the Steve phone, I may encase it in lucite)