A member of my team has just left as their contact was not renewed. I was their line manager. Our IT department has given me access to their emails for business reasons, I.e. in case I need to pick up any tasks. I have discovered that the ex employee has been spending core work time sending offensive emails about me to her friend. Not an isolated incident, they go back for months. I have a thick skin but these emails are really nasty. Definitely would have been a misconduct offence if employee was still here. Can I mention this if I am asked to provide a reference in future?
As far as I'm award you can be factual so I would state that after they left it came to light that they had been sending hundreds of inappropriate emails during work time criticising management using very personal language.
But I would also contact the ex employee and tell them that their reference would contain information about their emails found after they left. They could then choose not to use you as a reference.
Hmm. I wouldn't really. The only work-related problem with the emails is that the employee used her work email account to send them. If she was respectful and performed her role reasonably well, I'm not sure it's justified to give a bad reference based on some historical emails you've dug up that she may have had an expectation would be private (depending on the circumstances).
I'd give a neutral reference and leave it at that to be honest. Doesn't sound like she thought much of you, but in management that happens sometimes, and I'm not sure jeopardising her whole career over it is a proportionate reaction.
It also may not reflect brilliantly on you. You've been given access in case you need to pick up any tasks, and have instead been using that access to trawl through months of emails from this person to her friend.
A new employer who is sufficiently impressed by this person to offer them a job may put it down to a personality clash or bitterness on your part, rather than it actually being relevant information for them to know in terms of her capability to do the job they are offering her.
Their first reaction would be likely to be speaking to her about it and I can quite imagine someone explaining away the type of reference you're talking about as bitterness or something, rather than a solid piece of information about, for example, her performance in the job being of concern and being addressed in a formal process.
Refusing to give a reference at all is as bad as giving a bad one. Just confirm dates of employment and say your policy is only to give basic factual information. You don't need to sing her praises.
If you'd discovered that the employee had been all over Twitter slagging you off to the world, you might have a point, as that would have potentially had a damaging effect on the business.
But some private emails to a friend which no one else would have seen, and which you wouldn't even have known about had you not gone digging or if the employee had used a different email account? Unpleasant to read I know, but don't let that cloud your judgment. It does sound like you are reacting in a personal way rather than anything else.
I assume your company has an email policy around private use? You may want to remind people still there that mail can be monitored, and should not be used for personal use (depends exactly what the email policy says.)
It could also be an opportunity to consider a 360 degree review, where you get feedback from your team on how you're doing and whether they've got ideas on how things could be done better. Is there any grain of truth in the slagging off? It might just be a personality clash and she was blowing off steam, and you probably have a different perspective on the things she's mentioned - but equally, I've not worked with anyone who is actually perfect, so maybe there are things you can do differently, maybe communicating changes better or whatever.