The person behind the advances in profiling rape suspects is Anne Davies, one of the country's top analysts and criminal behavioural psychologists. She is helping the police to narrow down likely rape suspects in "stranger" attacks - traditionally among the most difficult cases to crack.
There were 33,500 reported sexual offences in England and Wales in 1997, including 6,700 rapes. About 80 per cent of rapes are solved - because most are carried out by someone known to the victim.
The new research for the Home Office involved the examination of 210 solved stranger sexual assaults involving a male assailant and a female victim. Most of the attacks took place in the Metropolitan police area, West Yorkshire, Humberside, Greater Manchester and Northumbria. The researchers found 84 per cent of the serious sexual offenders had a criminal record before they attacked a woman. Of those, nearly three-quarters (73 per cent) had convictions for theft, over half (56 per cent) for burglary, and exactly half for violence offences. Only a third of the sample had been caught and convicted for a previous sexual offence.
The findings have already proved useful in predicting likely suspects. The Home Office report, "Predicting the Criminal Record of a Stranger Rapist", concludes: "Analyses used in the study explicitly identify offending behaviours which, alone, or in combination, could suggest to an investigator that an offender would have previously come to the attention of the police for a particular type of crime."
Ms Davies' work, as head of analysis at the Metropolitan Police's directorate of intelligence, involves examining what a stranger rapist, sometimes a serial attacker, actually does and says. She examines statements from victims about how they coped and how the attacker behaved towards the victim.
One of the keys is whether there are indicators of previous criminal experience, for example if the man reveals he has knowledge of how the police will investigate the crime.
Ms Davies looks to see how the offender controls his victim - either verbally or via a weapon. The recent trial of the serial rapist Richard Baker heard how he loved to control his victims with threats.
The rapist's sexual behaviour also provides clues, including whether the woman was able to negotiate. "You are looking to see how violent he is and whether he has a previous record, or has beaten his wife.
"A lot of rapists often have difficulty in getting an erection. There's a gap between reality and fantasy," she explained. "Some do it for fun, it's a thrill. Others enjoy asking people whether they want to die. Someone who is turned on by death and dying is considered potentially very dangerous."
Clues to the social background of an offender are given by the level of intimacy and aggression. "You try to build a picture of the guy. You look for signs of planning and fantasy. If signs of planning it's likely he will do it again."
Ms Davies is keen to distance herself from the intuitive methods used by her television equivalent in Cracker.
She believes the techniques should become increasingly based on science. "Insights and intuition can lead to horrible mistakes - I think Cracker is just entertainment."