Witnesses at the scene where a car crashed into pedestrians near the Natural History Museum in west London have described a chaotic situation.
Police have now confirmed the South Kensington incident, in which 11 people were injured, was a road traffic accident.
But it sparked panic in an area popular with families and tourists, in a city that has faced a heightened terror threat in recent months.
Luke Garratt was nearby when the collision took place.
He said he was first alerted to what was happening when police cars arrived at the scene.
The incident left traffic gridlocked, but many tourists at the scene didn't seem concerned, he said.
"People seem quite calm," he said. "Lots of people don't really know what's going on. What they're seeing is just police telling them to move away."
Jayne Witherspoon was on the tube when the incident took place.
"The doors opened and about 50 people came running down the tube station escalator," she said.
"Some people were cowering in the walkway tunnels. It was just mass panic really."
Police cordons were set up outside the station and Ms Witherspoon saw one woman with a bandaged leg in a wheelchair, being attended to by ambulance staff.
"There's a lot of people milling about not knowing what's going on," she said.
Enamul Hoque was at a Chinese restaurant in the area.
He said customers "hit the floor" suddenly and people outside began running up Exhibition Road.
"The people just panicked, panicking and running really, they didn't really know what was going on," he said.
He said a large number of policemen asked diners to leave the restaurant, "leaving bags and things behind".
Mr Hoque added that he and his companion paid for their meal before leaving.
Maxime Latelier saw a man taken from a car and put onto the ground by a group of people.
He said police arrived 10 minutes later and after 30 minutes the street had been evacuated.
"When I heard the crash I saw people running," he reported.