Police launched a murder inquiry tonight after the body of a man was found when officers pulled over a van.
The body was found in the back of the white van when it was stopped in Sunningdale, Berkshire, shortly before 2pm.
A large section of the A30 London Road, near its junction with Cedar Drive, remained cordoned off for many hours.
Thames Valley Police said a murder inquiry had been launched and a number of people arrested after a body was discovered.
Eyewitness reports
Marketing manager John McCann, 38, said his wife Samantha, 38, saw the incident unfold as she walked to a cafe nearby.
He said: “As she came out from an alleyway on to the road she bumped into somebody who was one of the armed suspects.
“She noticed that there were three others already in custody, handcuffed by police and surrounded, and this guy was running away.
“The man was eventually caught and she thinks four people were eventually taken into custody.
“The rumour at the scene is that it is some sort of kidnap attempt but we do not know any more than that.”
Asked how his wife was, Mr McCann added: “She is fine. She was not scared or intimidated because she just thought someone bumped into her. “She had her back to him and it was only afterwards police told her he was armed with a gun.”
Channel 4 News understands that – contrary to some reports – the arrested men are not of eastern European origin.