Cheshire County Asylum, Chester
Now closed, this was once Cheshire's County Asylum. Lots of the 'usual' features found in such places, such as seclusion cells (one of which is painted with hazard stripes), a water tower and ward rooms.
This one's a good one because it hasn't been smashed up by morons. Just look at the lampshades in the photos, intact radiators and a minority of broken windows. Being based on a major NHS site and with some parts alarmed, it seems to have survived pretty well despite the peeling paint.
Last photo shows a strange cast iron dentists chair tucked away in the basement. Quite why that was down there I don't know, but it was certainly eerie.
Big thanks to BenWRX and Spook for leading the way.