Three years ago, at a TV "gab-fest" in Barcelona, I was very taken by a speech from the boss of Germany's most successful TV channel. Helmut Thoma, then the chief executive of RTL, said that there were only four ingredients needed to run a commercially profitable television channel in Europe. They were: sports rights, Hollywood movies, sex and crime. It was a rather blunt analysis, but it struck me as probably true. Sure enough, the first three items played a fairly prominent part in the early success of Britain's Channel 5, where I now work. But in the past year, the fourth ingredient has been added to the recipe - and with great results.
Crime has always featured heavily in British TV drama. Look through the schedules across the channels, and you will see how many of the prime-time dramas on ITV at the moment are about crime - just look at Inspector Morse, The Bill, The Knock, A Touch of Frost, Prime Suspect, Heartbeat, Midsomer Murders, Without Motive, Taggart and Wexford. Social concern programmes about crime have also figured large on British television. The BBC's Crimewatch is the doyenne of this genre, but ITV has also dabbled in the "keep 'em peeled" variety of crime show. But "true crime" television - of which Court TV is the prime example - is something else again, and it is proving exceptionally popular with viewers. It has introduced hundreds of hours of documentaries on the most notorious crimes of the 20th century. Serial murderers such as Ted Bundy, Jeffrey Dahmer, Charles Manson, John Wayne Gacy and the Boston Strangler are the "faces" of Court TV - and the viewers' appetite for their stories has helped Channel 5's prime-time ratings increase threefold in the past year.
Compared to costly drama, sports and first-run movies, factual crime programmes offer a much greater ratings return on investment. As a result, large chunks of satellite channels such as Sky 1, Discovery and Bravo are filled with the stuff, while ITV, Channel 4 and the BBC have so far confined themselves to smaller doses of true crime. None the less, you can expect them to pile in soon, too.
The availability of this "full-on" crime material to British audiences is comparatively new. Much of this material is imported or copied from the US, where the fascination with violent crime has thrived, unchecked by our rather more squeamish attitudes to this lurid subject matter. Fifty million American homes now have a channel devoted exclusively to the genre.
Free-to-air television in the US is a nipple-free viewing experience, but violent crime is regarded as a legitimate subject for family viewing if handled with some caution. Here, the position is reversed. We apparently have few problems with nipples, but violence is something else. A survey of viewers' attitudes by the Broadcasting Standards Commission, released last week, was the latest in a long line of reports which confirm that British audiences are far more offended by TV's portrayal of violence (50 per cent) than its portrayal of sex (42 per cent). Because of our regulations on taste and decency, the majority of imported American crime documentaries are only suitable for viewing late at night, and even then, with significant cuts.
And yet, and yet. Despite British protestations about our great antipathy to violence, the figures clearly tell us that this kind of programme is very compelling. Why?
The answer is fairly self-evident. We are all fascinated by the human condition, in sex, food, birth, death and violence. Crime - especially violent crime - is an extreme phenomenon of the human condition. We fear and so we want to know more about it. Manifestations of anti-social or evil behaviour enthral us. We want to know why people do wicked things. Are they "bad" or are they "mad"? The despicable crimes of Fred and Rosemary West reminded everyone that the most dreadful violence takes place in the most mundane of circumstances, and that family values can be twisted into something truly horrific.
This is the appeal of "true crime" and, in many ways, it is much more compelling than the fictional variety because we know that it really happened.
The current king of American crime drama is Dick Wolf, executive producer of the award-winning US hit series Law & Order, now in its tenth series. This year, he has returned to the real-life crime cases on which most of his earlier drama plots were based. He and the Law & Order writing team are now using their initial research to produce a series of crime documentaries liberally laced with dramatic reconstructions. In this way, the true crimes that inspired crime drama are now reverting to their original form and are being re-released as a factual series.
A less attractive explanation for the popularity of true crime is that it appeals to our baser instincts and that it is little more than a sick form of entertainment. Those who hold this view rightly point out that gruesome crimes are often sexual in nature, and tend to involve men doing unspeakable things to women. What they often fail to mention is that women appear to share this base fascination with men in equal proportion.
Take the viewing statistics for four of the most recent crime series on my own channel. Of the total audience, 49 per cent were men, 47 per cent women, and the remainder were children under the age of 16.
The age profile skews in the direction of older viewers, with roughly two-thirds of the audience aged 45 years and above. This last fact is often used to support another concern about "true crime" on television: that it creates a climate of unreasonable fear - particularly among the elderly - by preying on their sense of vulnerability.
The most recent Home Office survey shows that the fear of crime is indeed growing, but can we really blame television? The same survey showed that crime itself is actually declining. Violent crime fell by 4 per cent between 1997 and 1999; the figures also show that one-third of all these crimes were committed by someone known to the victim.
Interestingly, the fear of crime is especially strong in rural areas, where people are more isolated and where police response times are longer. Look at the huge outpouring of public anger over the jailing last April of Tony Martin, the Norfolk farmer who shot dead a young burglar who broke into his home.
The growing fear of crime strikes me as a problem for law enforcement, not for television executives. I get annoyed when people single out programmes like Crimewatch and praise them as a valuable public service, while condemning a straightforward profile of Harold Shipman as a piece of fear-mongering entertainment. I am much more alarmed by the kinds of crime that are the staple ingredient of Crimewatch. I genuinely do worry about burglary or drunken assault on the street - but I do not lie awake at night imagining myself as the casual victim of a deranged serial killer. When Nick Ross ends his programme with an exhortation to sleep tight and not to have nightmares, I feel a shiver go down my spine.
Crime - especially murder - is undeniably a very popular subject for television, but the public interest justification for making documentaries about it will always be controversial. I have a vested interest in this topic: I have always been fascinated by "true crime", and the genre is proving successful as part of my programming. So don't take it from me. Instead, I will leave the final word to Professor David Cantor, one of Britain's most respected criminologists and a contributor to a forthcoming programme on the crimes of Fred and Rosemary West.
"We will continue to see people like this, so the more we can get to grips with how they see the world, how they think, how they express themselves and, indeed, the details of their activities, the more it will enable us to understand what makes these people tick, and will help us to provide a framework that can be of real use to police investigations in the future."
Chris Shaw is the controller of news, current affairs and documentaries for Channel 5