Can give you an update on this story.
The roads are all open again following yesterday evening’s closure of the city’s central roads.

It wasn’t a sinkhole but an explosion that lifted pavement slabs outside the Guildhall.

That area is still cordoned off.
I’m waiting for a statement from B&NES.
It’s now 12.33 and nothing from B&NES. I don’t need them anymore.
I have been told that an underground electricity cable overheated and caused the explosion.