Not Shropshire but I had something very similar near the New Forest about three years back. Big, black, and moving with that low fluid gait that domestic cats just don't have - you know the one, where the shoulder blades are really working. Took me a second to even process what I was looking at because your brain initially tries to rationalise it as a dog or something.
The Shropshire hills are actually one of the more credible black cat corridors in England, there's been consistent sightings going back decades in that area. A lot of people think these are melanistic leopards or possibly pumas that got released after the 1976 Dangerous Wild Animals Act came in and owners panicked.
What struck me most was the tail - long and thick with a slight curve at the tip. Nothing like a dog. What distance were you at when you saw it? And what time of day, because that affects how much we can rule out misidentification.