Dozens of residents have to be evacuated from their homes in south west London after two multimillion-pound properties collapsed amid renovation work.
Dramatic pictures from the scene in Durham Place, Chelsea, show the mid-terrace buildings reduced to rubble after the “extremely loud” crash on Monday evening.
Firefighters said two four-storey properties that were under construction collapsed to the ground. One neighbour said workmen had been on site “for weeks”.
Around 40 people were evacuated from nearby properties, but there are no reports of any injuries.
One seven-bedroom house on the exclusive Durham Place sold last year with a value of around £16 million, according to figures on property website Rightmove. The damaged properties are thought to be worth around £4million.
Andrew Reeves, 58, a founder of property buying agency Totalis Prestige, was walking his daughter to school past the rubble this morning.
He told the Standard: “The road was closed off by the police and a few builders were milling around as next door is under renovation.
“I was told around 40 people were evacuated from nearby residences. Fortunately, no one was hurt.
“I noticed there was a builders sign saying ‘basements’. Maybe this has a bearing on the collapse? Having compared it against Streetview it would certainly appear to be two houses.”
A next door neighbour described how he heard what he thought was a “huge thunder clap”.
The neighbour, who returned home to recover his budgie, told the Standard: “There was a huge noise like a thunder clap. Then there was dust inside my home.
"I think the scaffolding went first. There has been a lot of work going on at the house. I have to stay elsewhere now.”
Another neighbour, 68, said: “There was an almighty crash that sounded like a bomb going off. There is too much development going on, it’s a nightmare. Kensington and Chelsea is one big building site.”
Richard Anooshian, from the Onslow Neighbourhood Association, which fights over-development in Kensington and Chelsea, visited the scene.
He said: “There is too much development. These developments compromise the structural integrity of the buildings.
"A lot of the development is for media rooms and fun things like that. Not usually so their 80-year-old granny can move in.”
The property remained behind a cordon today as structural engineers worked out how to make the building safe.
Land registry documents show the freehold is owned by real estate company Seabrook Properties Limited which was set up in the British Virgin Islands. A planning application for work on the lower ground floor and terrace, with a rear extension, had been approved by the council last year.
The council warned in the application letter that “if not properly managed, construction works can lead to significant negative impacts on the local environment, reducing residential amenity and the safe function of the highway”.
Three properties on the street, including one next door to the collapsed buildings, are currently undergoing basement excavations, according to planning documents submitted to Kensington and Chelsea council.
The planning application for the neighbouring property was made less than two weeks ago, with a council letter dated October 23 detailing “basement excavation, demolition of extension and roof terrace and replacement with a two-storey rear extension with roof terrace, and a single storey extension at the lower ground floor”.
It said a decision from the council was expected on November 19.
London Fire Brigade Station Commander Jason Jones said: “There was a total collapse of the building from the roof to ground level.
“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.
“Local road closures will remain in place this morning.”
A Metropolitan Police spokesman said: "Police were called at 11.25pm on Monday, November 2, to reports of a building collapsed in Durham Place, SW3.
"The occupants of neighbouring properties have been evacuated as a precaution.
"At this stage, there are no reported injuries and nobody is thought to have been inside the building. Emergency services remain at the scene."
A Kensington and Chelsea borough council spokeswoman said they had granted plants for a lower floor extension in 2018 in line with their policy of restricting basements to a single storey.
She added: “Our team worked through the night, opening an emergency rest centre for those affected and assessing the safety of surrounding buildings.
“Thankfully no-one was hurt and residents were able to return safely to their homes at 3am. The reason for the collapse is being investigated by the Health and Safety Executive.”