How police follow the plots of popular fiction

It's very much the feeling at present, in the wake of cases ranging from the horror of the Damilola Taylor murder to the farce of two silly royal butler theft cases, to consider that today's police detective work is not a patch on the sterling work of the good old days. Bitter comfort can then be taken in yesterday's verdict on John Allen, who it now emerges killed his wife and their two young children 27 years ago.

Allen, it appears, was a compulsive liar, who has been convicted for bigamy and fraud, and who had faked his suicide and invented a new identity for himself even before his wife and children disappeared.

The police suggest that we should not be too hard on them, as it was the Crown Prosecution Service, not they, who made the decision not to proceed with the case all those years ago. The police never closed the case, and eventually returned to the investigation to secure yesterday's verdict of guilty. Plucky, dogged, them. Hurrah! And indeed, it is true enough that the investigation was restarted because someone who had not co-operated with the police at the time finally admitted her suspicions.

This person was Eunice Chapman, Allen's mistress at the time of the murders, who continued to live with him for 12 years after the disappearance of his wife and children.

Even so, police reaction to Mrs Chapman's new evidence was far from swift. She had published a book, Presumed Dead, in 1992, in which she outlined her suspicions and reported that there were scratches on Allen's arms on the morning he said his wife had gone. Mrs Chapman says she kept her mouth shut at the time "out of loyalty".

There are certain things to be said about a mistress who blinds herself to the idea that a man may have slaughtered his wife, a five-year-old and a seven-year-old "out of loyalty", and no doubt there is much more for Mrs Chapman to relate about how she gradually came to recognise Allen not as a victim of suspicious minds but as, as she now describes him, a "psychopath". But at least, to her credit, she never forgot the woman and children whose lives were taken, and had the courage to do something to move the case on in the end.

Her book was published three years after her relationship with Allen had ended. But it took another seven years for the police to decide to act on the information in the book, and take a statement from her. Scratches, the police reckoned, were something, but not nearly enough. And then they had a brainwave. The story Allen had told the police in 1975 was that his wife had taken the children off to the US, to start a new life with an old boyfriend. This story had never been checked out. A belated link-up with the family of the US serviceman in question, Johnny Simone, revealed that he had suffered from a catastrophic stroke in 1972, three years before his old girlfriend had vanished. Who can say what the CPS might have decided all those years ago if anyone had thought to follow this line of inquiry back then?

What of it? Devon police, like the Mounties, got their man in the end, and very proud of it they seem. The police have even offered posthumous thanks to one of their officers, who is alleged to have done much – but clearly not enough – to bring Allen to justice back in the Seventies.

And it is true that back then the disappearance of Patricia Allen and her two young children was taken seriously. There was a massive search for the bodies, for example, which have never been found. But Allen seems to have been taken seriously too, in quite the wrong way. There appears to have been a huge tendency to give the prime suspect in the case the benefit of the doubt.

It seems amazing now that the story of a known liar in this situation was never verified. Perhaps back then there was a greater tendency to take a man at his word when he said that his wife was feckless and unpredictable, as well as a perception that the whole world was too big a place to start chasing around it in a search for lost kids.

Which can only mean that in at least these respects, things have improved since the Seventies. One thing that has not changed at all, though, is the vast extent to which our perception of police or detective procedure is influenced by its portrayal in popular culture. At the time of the murders of Patricia, Nicholas and Vicky Allen, the novels of Agatha Christie and Dorothy Sayers were all the rage. Both crime-writers relied very much on having amateur criminologists who always stayed one step ahead of the police.

In the Allen case, the entire town of Salcombe, where the family had made their home, seems to have been the home of amateur criminologists. Apparently the belief that Allen had killed his family was rife among the local people, even though there were no bodies. How awful it is that even with the evidence there, waiting to be found, such a suspicion could not be made to stick.

Now the trend is towards police procedural thrillers, in books and on television, showing fiendish crimes always solved by clever detective work from the professionals. It is strange that as public confidence in the ability of the police to solve crime has dwindled, our appetite for fictional portrayals of detection has moved away from the private operator running rings round officialdom to celebrate instead the triumph of the mainstream channels of detection.

A set-up such as the Allen case wouldn't get house-room in a Ruth Rendell or on one of Greg Dyke's Crime Doubles. The detective work involved in tracking down the truth would be far too childishly simple for there to be any dramatic tension at all. In a few transatlantic calls, the person who was most likely to be guilty would be sussed out as lying through his teeth, and that would be it.

And oddly enough, the pattern of popular crime fiction has played out to mirror reality exactly in the quarter of a century it has taken to solve this case. The Devon police found themselves unable to pin three murders on their suspect back in the days when it took a Belgian detective or an English aristocrat to show the fictional police what to do. But in an era that sees the police of popular culture solving crimes in a wink – or at least in a back-to-back two-nighter – the real chaps find the whole deal much easier.

So while the focus in the Allen case, now the trial is over, is on asking why it took 27 years for the crime to come to light, it might be more comforting for all of us to instead reflect on the idea that despite our gloomy beliefs, the police are in real life as in fiction actually less gullible, and better at solving crimes than they ever were in the past. Maybe the popular portrayal represents a truth that we are all too frightened and pessimistic to acknowledge.

This may seem much too far-fetched, in days when we accept that the people who smashed the windscreen and took the stereo, or knocked the old lady over and took her bag, will never be caught unless they are caught red-handed. But it is perfectly possible that while chaotic and random crime has made the detection figures look abysmal, the likelihood of a man slaughtering his wife and children and getting away with it for a quarter of a century have been ever-dwindling all the same.

There are not too many reasons to be cheerful in this season of goodwill, but maybe, despite initial appearances, the Allen case is one of them.

d.orr@independent.co.uk