remind her that if he gets reported to the police that he will be arrested for statuatory rape.
this will then come up on CRB checks and he will not be able to get a job with any culnerable person - be they children, patients, anyone in social services, the elderly, anyone with mental health issues - it closes a stupendous amount of doors for him.
remind her that it won't be you who tells the police, but it just takes her to tell a friend and the friends tells an adult - or he does the same and their worlds will come crashing down
meanwhile, you should look to getting your daughter on the pill/injection/implant
she might have sex - and this might be the last thing you want - but it doesn't mean that it won't happen.
better to prevent a pregnancy where possible.
Also tell her that if she loves him, she won't put him through the trauma of being arrested. that no matter how much he says its worth the risk, or it isn't a risk at all, if she really loved him, she would do whats in his best interest
reverse phychology there.
I would also be trying to make sure that her schedule is pretty full with fun things she likes to do - if you possibly can. thigns with her friends. perhaps inviting friends over, paying for them all to go to pictures etc.
do you happen to have a handy large DH? they can also act as a deterent in a 'touch my daughter before she is 16 and i will find you and do your fucking knee caps in' type of friendly chat.
but you must remain calm, YOU must remain in her confidence, you must be the one she asks for advice and she comes to in confidence.
If you have a dh or a dp - asking them to be the baddie is a rotten job - but someone has to lay down the boundries and someone has to remain in possession of as much information as possible - and its hard nigh impossible to be the good cop and the bad cop.
if she has a good relationship with granny, might be a thing to ask granny to be the good cop, shoulder to cry on, safe place to run away to.
there needs to be a person who will bite their lip, give sensible non judgemental advice so that your daughter will be forthcoming with details.
and its bloody hard, haring gory details whilst you just want to shake them and shoot the boyfriend/girlfriend.
but this is the thing to remember
if you want to keep your daughter or son - you have to be nice to the girlfriend/boyfriend - invite them round for tea, be interested int heir life etc.
and even if you hat them, if you want to remain on good terms, and still be a figure of importance in your teenagers life, this is what you have to do.