I am not in this position yet, but am interviewing for a few positions.
I wouldn't like to go into specifics, but I work in a small hellhole. The owner can be unpredictable and passive aggressive. He has in the past made a 'joke' he will give me a crap reference so I can't ever leave(in the context of complaining about staff retention). It might be unlikely, but if the time comes, I am worried he could be in his spiteful phase and just ignore the request. He also likes to make creepy jokes at and about me, so another thing I'm worried about, is if someone calls for a reference instead of email (do companies ever call?) he might make one of these 'joke comments' to the company.
For other people who have left, they haven't needed a reference because of the industry (their job interviews are more based on demonstrating the skill). Mine is office based work and the companies I am applying for will be rigorous with references.
He is already flouting many h&s responsibilities and such, so something like a reference he isn't obliged to give isn't going to worry him. The trouble is, almost all potential jobs require a current employer ref. I have been here just over a year, so I can't leave this job off my cv.
There is no one else in the company who can deal with references (well except me, but obvs not in this case).
This job has taken a toll on my MH so I am probably being over anxious, but I would still like to prepare just incase.