A Man was arrested last night in connection with an incident in which two robbers were shot dead when armed police foiled a raid on a security van outside a bank.
Scotland Yard said they had arrested a man in the Raynes Park area of London.
A gang is believed to have targeted the van as it called at a branch of the HSBC in Bournemouth Road, Chandlers Ford, Hampshire, at about 10am.
The Independent Police Complaints Commission (IPCC) has launched an investigation into the shooting which happened during a planned operation between the Metropolitan Police Flying Squad and Hampshire Constabulary.
Eyewitnesses claimed they saw a third man fleeing the scene which one described as a "bloodbath".
Witnesses described one of the robbers holding a gun to the head of a security guard when he was shot by police.
Passers-by said they heard shots being fired before up to 30 plain-clothes police officers wearing Metropolitan Police caps rushed into the area.
Attempts were made to resuscitate the two men who were lying in the street in pools of blood, said witnesses. One man died at the scene, the second in hospital, police said.
A Scotland Yard spokesman said: "The object of the operation was to prevent and apprehend those believed to be involved in an attempted armed robbery of a premises in Chandlers Ford.
"At about 10.05am, shots were fired and two men were shot. One was pronounced dead at the scene, the other was taken to a local hospital but died at approximately midday.
"No officers were injured in the incident. The incident has been referred to the IPCC."
The spokesman refused to comment on witness claims that a third robber had made a getaway from the scene.
Police said last night they wanted to locate a blue Volvo estate motor vehicle, bearing the registration OY05 WDU.
Residents Lynn Ward, who works at the Alexander Keen estate agents next door to the bank, said she heard a loud bang and then shouts of "get down".
"I heard a loud bang ring out and initially thought it must be a traffic accident," she said.
"But when I looked out of the window I saw a security van and two people on the floor with armed police stood over them. It was chaos and there was lots of shouting and screaming."
A spokesman for HSBC confirmed no customers or staff were hurt.