I remember this one is very dimly. I was recording it on Betamax, it was that long ago. We kept Betamax very late, though, so this was on TV in probably the mid to late 80s. I wouldn't swear it wasn't very early 90s, but probably not. I only watched the first five minutes; I would have been a small kid and wasn't allowed to watch the rest. I've wanted to track it down ever since.
It was live-action, sci-fi, American. The opening scene, or a scene very near the beginning, involved a gloomy, generically sci-fi torture chamber with a guy strapped to a table in the middle, and a genial torturer demanding information and calling for various tortures to be applied. One of them was called "ultra[something] slime." The guy on the table is screaming "no, no," and refusing to answer. It was a fairly standard torture scene.
I remember it looking reasonably well produced, film-originated, gloomy, shadowy, grey in tone, no bright colours. Lancing beams of light. Probably an 80s movie. I felt like it was shaping up to be post-apocalyptic, but I'm not sure. My recollections could be very inaccurate as this is thirty years ago and I was probably eight, so this is a very long shot, but any ideas gratefully received.
I've never seen it since this one UK broadcast at that time, so I'm fairly sure it isn't any of the well-known 80s sci-fi. It isn't Millennium, but it looked a bit like it, production-design-wise.