I was at work one night about 3 years ago in a prison in the West Midlands and I had to do hourly obs on a prisoner. And I had to check on the person at 03:00. Our office was on the first floor and he was on the ground. When I went to walk down the stairs I was met with what I can only describe as a human form but it was bathed in a bright white light. My whole body covered in goosebumps. It spotted me and fled activating the light sensors when it went.
I wasn't frightened but I have never been able to have an explanation of what I've seen.
Previously to this I worked at an old victorian prison locally. The other houseblocked I worked in on nights I was with another officer so it was like someone was watching me but I felt safer. Anyway this one night I was in a building on my own again at 03:00 I heard things being thrown like bricks outside the office I was in, people talking and walking around on the landing and up and down the stairs this went on for a considerable amount of time. I again had to check on someone at 05:00 which was on the fourth floor I walked up there to his door looked through the flap and someone grabbed my shoulder. I could feel the fingers on me and I turned around but no-one was there. That was the last time I worked there as there had been other things happening in daylight hours. The prison used to hang people and some of them were buried within the grounds. A very creepy place but some people had been working there for years and never experienced the things I did there.