Adam’s Walk in Kingston town centre was closed by police and three men were taken to hospital after what officers believe was a reaction to "dodgy drugs" this afternoon.
Police and London Ambulance Service paramedics were called to the arcade, off Eden Street, just before 3pm to reports of "four or five" men "slumped in the road".
London Ambulance Service's press team was unavailable to provide full details.
Laurence Antwi, worker at Moss in Eden Steet, said: "We heard them screaming, I didn’t know how many there were, you could hear the sound.
"We didn’t know nothing [when the police arrived], we just received information to shut our door and that’s it."
A police sniffer dog could be seen in Adam's Walk. Pic: Jon Mitchell
Kingston police tweeted: "Police called to four people unconscious on the floor fitting, believed that they have taken shared drugs.
"No other members of the public involved / at risk."
Witnesses reported seeing between four and six people looking extremely ill and fitting outside the arcade.
Passer-by Melissa Moody said: "[Someone] was saying that he knew four of the men and that they had taken legal highs, after which they collapsed.
"While I was there a fifth man was found and taken to the scene. There were at least five police cars and three ambulances."
UPDATE: Adams Walk - Police called to four people unconscious on the floor fitting, believed that they have taken shared drugs. 1/2— Kingston Police (@MPSKingston) January 27, 2016
UPDATE: No other members of the public involved / at risk. We are still on scene dealing with @Ldn_Ambulance 2/2— Kingston Police (@MPSKingston) January 27, 2016
A Metropolitan police spokesman said: “We were called by members of the public concerned about the welfare of four men.
"The suspicion is they have taken some dodgy drugs.
"They didn’t seem very well at all. We are trying to get these people into ambulances to get them looked at by LAS."
Pic: Jon Mitchell
Sophiane Bessa, who works at Charles Birch Scotland – a shoe repair and key cutting shop in Adam’s Walk – said: "I had seen a couple of guys standing outside and then I had a car key to do so I went to the back, locked the shop, started with the car key.
"When I came back I found one person fallen next to the shop and then I saw others nearby.
"I just missed it and came back and there was panic over the arcade."
He added that the people looked to be in their mid-40s.
Adam's Walk was reopened to the public just after 5.30pm.
A London Ambulance Service spokesman said: "We were called at 2.58pm to reports of an incident involving men in Adam's Walk, Kingston.
"Our crew were on scene within two minutes.
"We took two men to Kingston Hospital and one to St George's as a priority."
- Did you see what happened? Call the newsdesk on 020 8722 6318 or email email@example.com