Don't take this as formal legal advice, but with very limited exceptions (you're not allowed to take your own recording of court proceedings, for example), it is legal to record a conversation you are having with someone. So the advice you've been given on that is wrong. Things become a little murkier legally when it comes to how you're going to use that recording. Publishing such recordings without permission can give rise to a civil cause of action (i.e. you can be sued for it) or it can in some circumstances be a criminal offence. But all of that depends on the circumstances behind and around publishing it. But as I say, the recording itself is legal. If you're doing it to do something like gather more evidence of harassment, that is absolutely fine. And chances are, taking that recording to the police, your employer, school or college etc for the purposes of them using it to take action against that person is also going to be fine.