An altercation between two men was what sparked panic among Christmas shoppers on London's Oxford Street prompting an evacuation of a packed tube station with police finding no evidence of gunfire or casualties.
The incident came at dusk on Friday as shoppers crammed the festively lit shopping strip and Oxford Circus tube station, leaving several people injured, with nine needing hospital attention, one with leg injuries.
Armed police raced to the area after receiving a number of emergency calls reporting that shots had been fired but about 90 minutes later had found no evidence of shots, casualties or suspects and the station was reopened.
British Transport Police say the incident is believed to have started with an altercation between two men on a platform.
"Thank you to everyone for bearing with us this evening and also to colleagues from all the emergency services who helped carry out a swift response," Chief Superintendent Martin Fry said.
"I know incidents like these can cause concern, but our officers are highly visible around the network and across the country."
Stuart Crichton, London Ambulance Service assistant director of operations, said: "We checked over and treated several patients who sustained injuries while leaving the Oxford Circus area.
"We discharged seven patients at the scene and took eight patients to two central London hospitals for minor injuries.
"We also took one patient to a major trauma centre for leg injuries."
The Met issued a statement saying officers had responded as if the incident was terrorism.
"Given the nature of the information received, the Met responded in line with our existing operation as if the incident was terrorism, including the deployment of armed officers," the statement said.
"Officers working with colleagues from British Transport Police carried out an urgent search of the area. No casualties, evidence of any shots fired or any suspects were located by police."
BBC producer Helen Bushby was in the area when the mass stamped began.
"I was just walking down from the BBC towards the Tube and there was a mass stampede away from the Tube as fast as they could," she said.
"They were crying, they were screaming, they were dropping their shopping bags. It was a very panicked scene.
"People said they heard a gunshot and panic was just spreading."