DOORSTEP con artists are prepared to travel hundreds of miles to carry out their evil trade.

Research by police shows bogus callers and cowboy builders would generally not operate near their own homes.

Instead, they will often travel across many counties to find targets in communities close to major roads.

There, they can be in and out of a house and be hundreds of miles away before a victim realises they have been conned.

This method means the criminals are seldom caught and can cause a major headache for police.

Statistics from Durham Constabulary - loosely mirrored throughout the country - show a detection rate of about ten per cent for crimes of "misrepresentation" compared to 22 per cent for burglary.

Detective Chief Superintendent Ian Scott concedes the police have a difficult job catching offenders.

"People we have arrested and charged come from areas such as Merseyside, Middlesex, Hertfordshire and South Yorkshire," he said. "That makes it increasingly difficult to link offences.

"There is intelligence to say that people involved in these offences will visit an area and almost do reconnaissance, not commit a crime, but identify vulnerable areas for a second visit. Also, there are those people who have been successful in an area who will then pass on details to other gangs, saying: 'There is easy money there'."

Retired Detective Chief Superintendent Brian Steele is now a Home Office advisor on doorstep crime, after having spent 32 years with the West Yorkshire force.

He has interviewed offenders in prison and had a weighty report published in which the criminals explain how they select houses and how far they would be prepared to go to get what they want.

Many of the conmen - both bogus officials and, especially, crooked home maintenance workers - have been brought up with a life of crime.

"This report reveals a disturbing picture of organised, professional criminals specialising in the commission of bogus offences against older adults, and especially targeting those whose frail and isolated lifestyle makes them vulnerable," the conclusion said.

"Many of these criminals commence committing bogus offences as early as seven or eight years of age and are often taught their criminal skills by a relative or family friend."

Of the 21 prisoners Mr Steele interviewed, 11 were members of the travelling community, and of the remaining ten, eight were of fixed address but drove long distances from their homes to commit their crimes.

The remaining two were not members of the travelling community but travelled extensively throughout the country, staying for short periods at lodging houses and hotels before moving on.

Mr Steele's report said: "The most obvious differentiation between offender types is the segregation of those who commit distraction burglary offences from those who commit bogus property repair crimes.

"Most bogus property repair offenders will commit a distraction burglary if the opportunity arises, whereas those who specialise in distraction burglaries are usually unable to commit bogus property-type crimes because they do not have the tools and other props needed to purport to be tradesmen.

"Some of these criminals travel great distances to commit crime and it appears that only the less professional criminals commit crime in the locality in which they predominantly reside."

* Tomorrow - Jailed conmen tell of their pride in their 'work'.