A police helicopter circled low over Surbiton last night as residents looked on.
Surrey Police said the police presence in Cottage Grove was connected to a search for a missing person.
Cottage Grove. Photo courtesy of @IBwan on Twitter.
But a witness said they saw a person put into a police van in Cottage Grove at about 10.30pm after it pulled up with a number of cars.
They said: "They walked to the back of the van and never reappeared. He wasn't in uniform. He could have been a plain-clothes policeman.
"It seems very strange, the whole thing."
The Metropolitan Police said this morning they had no record of the incident.
A separate call to Surrey Police from Effingham Road, shortly before 11pm, was unconnected to the Cottage Grove incident, a spokeswoman said.
A South East Coast Ambulance spokesman said paramedics were called to reports of a man in his 60s having suffered a fall.
Police officers attended first and the man did not need treatment, he added.
Did you see what happened? Contact the newsdesk by calling 020 8744 4273 or emailing firstname.lastname@example.org.