I think this was the collapse of the property in Perceval Terrace. At the time it was a Students' hall of residence for Brighton Polytechnic, now Uni of Brighton. Fortunately no-one was hurt although the building was in use at the time. Think it was probably in the 1980's. A large hole had appeared in the ground and the front of the building collapsed into it. The property was rebuilt to look exactly the same and looking at the row now, you wouldn't be able to tell.