Two people have died and a further six people were injured as balcony collapsed in Knightsbridge, London Ambulance Service said.
Emergency services were called to Cadogan Square, Knightsbridge in south-west London, where paramedics treated eight people.
Despite efforts by the London Ambulance Service to resuscitate one man, he died at the scene.
Another man was taken to hospital but later died of his injuries, while six other people were treated for minor injuries but did not need to be taken to hospital.
Both the men who died are believed to be removal men.
A LAS spokesman said: "Sadly, a man died at the scene.
"We sent three ambulance crews, an advanced paramedic, the hazardous response team and a London air ambulance.
"We treated eight people. Every effort was made to resuscitate a patient.
"Another man was taken to St Mary's Hospital."
The Health and Safety Executive and the Local Authority have been informed. An investigation is underway to establish the circumstances.