Experts believe that more than 30 assassinations take place in Britain every year by an estimated 20 active professionals. The bodies are sometimes never found.
The murder of Jill Dando closely matches the blueprint for a professional hit, in terms of location, timing and method of execution.
Detectives say that typically, victims are targeted on their doorsteps as they arrive home or answer a knock at the door. The 9mm semi-automatic is, along with the old-fashioned revolver, the contract killer's weapon of choice. The US-made Browning, though illegal in the wake of Dunblane, is widely available for as little as pounds 250 on the black market. Originally issued to British servicemen in the 1950s it is still in use by the Army.
Ms Dando's murderer also followed the first rule of such executions, which is to fire from point-blank range.
But instead of using a motor cycle for a quick getaway and wearing a crash helmet to hide his face, as is usual for hitmen, Ms Dando's murderer apparently lingered in the street, undisguised, before the killing, and left the scene on foot.
According to Ian McKenzie, deputy director of the Institute of Criminal Justice Studies at the University of Portsmouth, hitmen are usually low- level criminals, who are expendable if killings go wrong and who cannot be readily linked to those who paid for the hit.
He said: "They will necessarily have some expertise with firearms and may have a military background. They are also psychopaths who have lost, or never had, any concern about the sanctity of human life."
Terence Morris, emeritus professor in criminology at the London School of Economics, said such people were readily available among the "heavies" used by criminals in the drugs and entertainment trades.
He said: "The growth of clubs has produced enforcers who regard injuring people as part of their job."
Professor Morris said the expansion in contract killing has been driven by the growth in the drugs trade. But professional hits can be linked to anything from international terrorism to a domestic dispute.
Automatic weapons, smuggled from eastern Europe, are freely available.
Many hitmen are never caught, although Kevin Lane, 26, known as "The Executioner", was jailed in 1996 for the murder of the millionaire businessman Robert Magill, who was shot while walking his dog.Reuse content