A ”substantial” void the length of a bus was detected beneath Dundee’s Albert Street after a pothole caved in, revealing the underground danger.
Police were alerted to the hole by a bus driver on Saturday afternoon and quickly called out a council engineer, who shut the road.
A spokesman for Tayside Police said: ”We got a phone call from the bus company to say Albert Street was collapsing.
”There’s a pothole but underneath there’s a void the size of a double decker bus.”
Barman Paul Gowans (44), who works at the nearby Windsor, watched the drama.
”It was just water seeping out of the ground,” he said. ”I was popping in and out of the pub but I believe it opened fairly quickly.
”I did hear the guys saying there’s a big void under it.”
The hole on the surface, thought to be caused by a water leak, was only around two feet square but investigations soon revealed the scale of the underground cavity.
Andy Scrimgeour, assistant engineer with the roads department, last night said: ”There’s a void under the road the length of a bus.
”It first became apparent yesterday afternoon. I received a call at 3.40pm.
”I had a look and initially I couldn’t see down so I initially closed the road southways.”
Further explorations though revealed the extent of the potential danger.
”It’s a substantial void, making it very dangerous,” Mr Scrimgeour said.
”There’s nothing there. There’s a water leak in the road there.
”What’s probably happened over time is the constant water pressure has washed away the structure. The road starts to fall in.
”I’m just grateful it didn’t fall in while a lorry was going over.”
Albert Street is a major arterial route.
Mr Scrimgeour closed the road fully between Raglan Street and the junction with Arbroath Road on Saturday night and the ambulance and fire services were made aware of the diversion down Lyon Street.
He said: ”I had to take the step to close the road in the interest of public safety.
”I would imagine that the road will certainly be closed for the next few days at least.”
However, one white van driver flouted the closure yesterday and was caught on police CCTV moving the barrier to reach a business in the blocked-off stretch of road.
The police spokesman said: ”We saw him on the cameras and sent police officers to have a strong word with him.”
Resources were limited over the weekend but Mr Scrimgeour said a meeting would take place, hopefully today, with Scottish Water and the roads maintenance team.
A spokesman for Scottish Water last night said: ”Scottish Water will work closely with Dundee City Council roads department to identify the potential source of this issue.”