But police are reportedly not treating the incident on Saturday as terrorist-related, even after a series of vehicle attacks on popular tourist sites in the United Kingdom capital.
He said he was first alerted to what was happening when police cars arrived at the scene. He has not been charged.
London Ambulance Service said 11 people were treated for injuries.
Britain has suffered five attacks blamed on terrorism so far this year, three of which involved vehicles, and the incident in an area packed with tourists at the weekend had prompted concerns that the collision had been a deliberate act.
SEVERAL people are injured and a taxi driver has been detained after a auto rammed into crowds outside London's Natural History Museum.
The incident caused panic on the crowded street outside the museum on Saturday afternoon.
He said he believed the auto involved in the collision was a grey saloon, which is now boxed in behind four police cars, although he did not see the collision.
Emergency servics were said to be on the scene outside the museum.
It is understood the vehicle mounted the pavement as visitors made their way to the museum, in west London.
Witnesses reported by some media said they had heard a loud bang. "And it was busy, people were having to struggle to get out of there".
"It was quite scary", he said.
Many shops in the museum district were evacuated and the museum was shut down as police tried to determine if there was a threat to the public.
An injured woman is wheeled away. She did not appear to be seriously injured.
One person has been detained by the police.
According to police, "several" people were injured.
Like the Victoria and Albert and Science museums - the Natural History Museum does not charge an entry fee but does charge for admission to certain exhibitions.
"Police have confirmed that today's incident at Exhibition Road is not terrorist-related and is being treated as a road-traffic collision", London Mayor Sadiq Khan tweeted.
Metropolitan police, however, could not provide the actual number of casualties.
Police officers stand guard after the incident.
THE organiser of Wemsfest has told of the aftermath of the incident at the Natural History Museum in London earlier today.