Five people were injured during a rehearsal for Queen Elizabeth II’s Trooping the Colour parade in central London on Saturday after witnesses said a stand collapsed.
Two of the casualties were taken to hospital after the incident near Buckingham Palace, a royal residence.
A small crowd had turned up to watch the rehearsal for this year’s Trooping The Colour, which celebrates the queen’s official birthday and is one of the most high profile events in her platinum jubilee celebrations.
Witnesses said crowds were moved by emergency services and the ceremony, which involves a parade by the Household Division and Horse Guards, was cut short.
“There was a loud bang, then a scream and a voice shouting 'Help, help'. A number of ambulances were at that location and stretchers were brought out for the casualties,” one witness said.
Footage shared on Twitter showed people walking through Horse Guards Parade, away from empty stands.
“Was fun experience to watch until we stood up for the national anthem, [then] the stand next to us collapsed with someone falling through,” one Twitter user wrote.
“They cut the proceedings short, and police began evacuating us for safety concerns as there had already been two collapses with fear of more.
“Was certainly a 'very British' experience with us queuing for an hour to watch marching horses and soldiers.”
Three people were treated at the scene in Horse Guards Road at about 11am on Saturday, London Ambulance Service said.
“We worked alongside St John Ambulance volunteers to treat five people at the scene,” a London Ambulance Service spokesman said.
“We took one patient to a major trauma centre as a priority. St John Ambulance took a second patient to a major trauma centre as a priority. We discharged three patients at the scene.”
A Ministry of Defence spokesman said it was supporting the emergency services following an incident on the Horse Guards Parade square.
“It would be inappropriate to comment further at this time.”