Homes were evacuated in London on Monday night after two four-storey townhouses worth millions of pounds collapsed in affluent Chelsea.
The two properties, which were undergoing renovation work to build a basement, collapsed “from roof to ground level” shortly before midnight.
Firefighters said about 40 people had to leave their homes and a 25-metre cordon was set up.
London Fire Station commander Jason Jones said there were no injuries.
“There was a total collapse of the building from the roof to ground level," Mr Jones said.
"Firefighters worked to make the scene safe and our drone team carried out a search.
“A police search dog also carried out an external search of the building and at this stage, there are no reports of any injuries.
"Nobody is thought to have been inside the building at the time of the collapse.”
One witness told the BBC the collapse was "extremely loud" with a lot of dust being kicked up.
"There were a lot of people coming out of their homes in the surrounding area to see what was going on. It was quite bad, really surreal," he said.
The collapsed buildings form part of a terrace of houses that was built in the late 1700s, opposite land owned by the Royal Hospital Chelsea.
A seven-bedroom house in the block sold for £16 million ($20.8m) last year, according to British property website Rightmove.
