I was surprised to read this story came from a British document. Does this mean it is true? If so that really underlines the reality of beings we are unaware of. Wither they are from off world or evolved here. If there were aliens or a small race of beings that wanted to stay hidden, choosing an underground situation would be the best place to hide for sure. There's been a lot of people who claim to have seen these creatures.
Yes, back in the early internet years (1990s) there was a lot of material on the net about this but now most of that has disappeared or is scarce so few people seem to be aware of it. This only heightens my suspicions that it may be true.