Charles Bunyasi, 49, was left lying in the road with "catastrophic head injuries" after being hit by the white Transit van.

The victim, whose oldest child is 16, was working as a delivery driver at weekends to supplement his council worker's wage.

He was taken to hospital but died of his injuries with his devastated wife at his bedside. Police arrested a 28-year-old man on suspicion of murder after he handed himself in yesterday.

Detective Chief Inspector Cliff Lyons, of Scotland Yard's Homicide and Serious Crime Command, who is leading the murder inquiry, described Mr Bunyasi as "an honest man making an honest living" when his van was stolen.

He added: "He was returning to the vehicle and as a result the thief ran over him, causing him catastrophic injuries.

"He lost his life because of the callous criminal actions of another person.

"The consequences for the family are far-reaching."

Mr Bunyasi had been delivering flowers near Coulsdon Manor Golf Club in the affluent village of Coulsdon, South London.

He lived with his wife and three children in nearby Mitcham. He was taken to St George's Hospital, Tooting, but died six hours later at 5:45pm on Saturday.

A postmortem to establish the cause of death was due to take place today

DCI Lyons added: "A man being sought by police surrendered himself around 24 hours after the incident. He has been arrested on suspicion of murder and is in custody."

Mr Bunyasi's van, which was being sought by police, was found last night three miles away in Purley.

Anyone with information is asked to contact the incident room on 020 8721 4961 or speak to Crimestoppers, anonymously, on 0800 555 111.