Witnesses and footage posted on social media suggested that the man was pinned down on the ground by passers-by in the busy tourist spot.
“The incident is a road traffic investigation and not a terrorist-related incident,” London’s Metropolitan Police said in a statement. “Whilst enquiries continue it is believed a car mounted the pavement and collided with a number of pedestrians.”
He is currently in custody at a London police station.
The London Ambulance Service said its emergency crews “treated 11 patients, mostly for leg and head injuries, and took nine of them to hospital”.
No one is believed to have life-threatening or life-changing injuries.
The Natural History Museum is located on Exhibition Road in South Kensington, one of the British capital’s most upmarket districts and home to a host of other Museums, restaurants as well as university buildings.
It is the fourth most popular tourist attraction in the United Kingdom, with 4.6mn visits during 2016, according to the Association of Leading Visitor Attractions.
Footage and photographs posted on Twitter showed the detained man next to a black car with its door open and its bonnet severely damaged.
Witnesses reported by some media said they had heard a loud bang, while an AFP reporter said crowds in the area had fled screaming in panic.
Armed police were deployed to the scene and the whole area was cordoned off.
Security is high in Britain after five terror attacks since March – four of them in London and one in Manchester – with the bloodshed claiming 35 lives.
Three of the attacks in London involved the use of a vehicle to plough into pedestrians.
Prime Minister Theresa May offered her thanks to the emergency services, adding: “My thoughts are with the injured.”
London’s Metropolitan Police said they were called to the scene at 2.21pm (1321 GMT) after reports of a collision.
One witness, identified only as Katy, told LBC London radio that she had seen two people injured, including a young boy whose leg was hurt and a woman.
Another who gave his name only as Leonard, told AFP: “I was near South Ken station and there were many police.
“Suddenly a police woman officer shouted at the crowd to run, and everybody flew in panic, many people screaming.”
“We heard what I thought was gunshots and saw a car drive over the pavement,” the BBC quoted one witness who was walking along the street to the Science Museum, which is next to the Natural History Museum, as saying.
“We just ran,” she said, adding: “My friend dived on the floor and cut her hands.”
“When (the situation) calmed down, we walked back to where we’d been and saw a gentleman on the floor being restrained by police,” she said.
A spokesman for the Natural History Museum told AFP: “I can confirm that there has been a vehicle collision with pedestrians on our Exhibition Road entrance.”
Not far away, tens of thousands of football fans took part in a silent protest “against extremism”, walking from Park Lane past Downing Street and to parliament.
The Football Lads Alliance was formed after the London Bridge attack in June and brought together supporters of rival teams with military veterans.
Ahead of the march, founder John Meighan said the group wished to “show our concern at the recent upsurge in terror attacks taking place across the UK and Europe”.
