These days inexplicable malice isn't a disadvantage but a recommendatio n when it comes to murder ...
In 1946 George Orwell wrote what was to become a celebrated essay lamenting "The Decline of the English Murder". The burden of his piece was that a ritual English pleasure - one to be numbered along with warm beer and cycling to Evensong, I suppose - had been devalued by Americanisation. Settling down after the roast beef, the reader of the News of the World could no longer depend on a "really good murder". And Orwell exemplified the falling-off in standards by contrasting an "Elizabethan" period of domestic crime with a recent scandal - the Cleft Chin Murder, in which an American deserter and a wannabe English showgirl went on a spree of robbery and violence. The arbitrary nature of this killing - there was no particular motive and no particular attempt at concealment - dispensed with all the elements Orwell had identified as essential to the classic murder.

And he was surely right to see that a change was in the air. In recent decades the murders of choice for the discerning public have involved just such random collisions between victim and killer. The enormous interest in serial killers - both in fiction and fact - indicates that the central notion of the "good murder" has changed and that is reflected by what we choose to transform into entertainment. These days inexplicable malice isn't a disadvantage but a positive recommendation. Though many of the classic cases Orwell cited have been the subject of television programmes none of them, so far as I know, have made it on to the big screen. But the case Orwell used as evidence of the decline did - it was made into Chicago Joe and the Showgirl, a not particularly successful British movie that obviously hoped to exploit a parochial angle on the well-established genre of the spree-killers (of which the canonical work remains Terence Malick's Badlands). What's more, the only recent British film about a poisoner ("The means chosen should, of course, involve poison" Orwell wrote) involved the case of the serial killer Graham Young, who graduated from domestic poisoning to the arbitrary poisoning of his workmates.

I think Orwell might have been encouraged, though, by the very considerable coverage given to the Lady in the Lake story, the recent case in which the discovery of a body in Coniston Water led to the charging of the dead woman's former husband, Gordon Park. I don't want to be flippant about this. The fact that 21 years have passed since Carol Park disappeared clearly does something to sterilise the case for the general public - to put distance between the horror of the crime and our fascination in reading about it. But the delayed revelation is not likely to make things any easier for her now grown-up children. Nor should we make any casual assumptions about the outcome of the case - if the past 10 years have taught us anything it is that not even a guilty verdict - let alone an initial charge - can be relied on as proof of anything.

But, whatever happens next, it is clear that so far the case meets Orwell's requirements very closely. Identifying the components of the "perfect murder" he wrote: "The murderer should be a little man of the professional class - a dentist or a solicitor, say - living an intensely respectable life somewhere in the suburbs, and preferably in a semi-detached house ... Having decided on murder, he should plan it all with the utmost cunning, and only slip up over some tiny, unforeseeable detail." Gordon Park is a retired ex-teacher who had remarried, lives in a semi-detached house and was arrested - in a sublime detail - on his return from a tandem cycling holiday in France. Is there any vehicle more respectably uxorious than a tandem, the mechanical equivalent of a Derby and Joan club? What's more whoever did kill the first Mrs Park presumably did not foresee that amateur scuba-diving would grow in popularity so much or that her dentist would prove quite so retentive about his records; but for a dusty X-ray pulled out of his garage it would presumably have been almost impossible to identify the body in the lake.

Of course there's another element to this crime - one which Orwell didn't specifically single out in his desideratum but which is clearly implicit in many of his cases, and that is a certain amount of delay between the deed and its discovery. When the gap is very long the essential frisson of the classic domestic murder - that your neighbour might not be quite as ordinary as you assume - is enormously amplified. Cases in which crimes are discovered after years of indifference or amnesia satisfy two contradictory feelings in us - that justice will eventually catch up with the guilty and that it might actually be possible to get away with such a crime. This is why the contingency of the betraying detail is so important to the effect - because it points up the fact that murderers can live lives of exemplary respectability. The exit from normality proves to be a revolving door - which will readmit the murderer after he has popped out to do his business. In this respect the finest Orwellian murder of recent years was the one reported a few years ago. As I remember the story, a peat- cutter in Cheshire accidentally turned up a body in a bog. This discovery was widely reported in the local papers and after a short time a man turned up at a local police station, ready to confess to the murder of his wife some 20 years previously. He had buried her in the same location and was convinced that it was only a matter of time before he was arrested and charged. It was only after the truth of his story had been established that it was revealed that the body in the bog belonged to someone who had been dead for hundreds of yearsn