Let me pitch some ideas. You are a commissioning editor, looking desperately for a fresh angle on the old genres. You are also indifferent to recent mutterings that the medium has become obsessed with detectives and police series. After all, you know that the public loves crime drama, and the prospect of some mild tutting from the Independent Television Commission troubles you far less than the terrifying thought that your rivals might find next year's fashion first. So here are some suggestions.
First, what about John Thaw as a military policeman? Peculiarly unpopular figure, I know, but you could work with that, draw something Morse-like out of the contrast between the unyielding discipline of the uniform and the tender, troubled heart within. Terrific global locations, too, which will give you a Soldier, Soldier feel, and it's pretty topical, what with the murders in Cyprus and Private Lee Clegg. The stories virtually write themselves - what about a murder in Bosnia, which turns out to have been committed by a frustrated peacekeeper taking retaliation? What about a racketeering scam in Belfast, suddenly exposed by the peace process?
If you don't like that, how about a series based around industrial espionage? I am really excited about this, I have to tell you. We are smack in the middle of the Eighties hangover, worried about greed and ethics and the money culture. And the international marketplace is the Second World War by other means. What are the Germans up to, everyone asks, and when does the next big push come from the Japanese? You get everything: boardroom intrigue, cutting edge technology, commercial ethics and gizmos, too - bugged pens and grungy hackers. I reckon Trevor Eve to front it, with a fat guy and a black girl as back-up. He could be having an affair with the black girl, to give a bit of back story. Hell, he could be having an affair with the fat guy, too, if you think the audience is ready.
No? Well, what about a series based on the emergence of forensic science in Victorian London? Remember, The Alienist is a bestseller and later this year Carlton has got Bramwell, a series about a Victorian woman surgeon. Corsets are going to be big. The angle here is to get beneath the standard Victoriana into something more accurate, the world of Mayhew not Conan Doyle. You have this dark squalor up against the new science. It is an inverted nostalgia - however bad the present is, the past was worse. There is also a sort of buried "Two Nations" thing there which might touch a nerve. Think about it, anyway. Call me.
At which point the more experienced commissioning editor might point out that every one of these programmes has already been broadcast. The youthful John Thaw appeared in Redcap in 1965, though ABC's budgets meant that Germany and Borneo had to be re-created in the studio. A year later Edward Judd turned up in Intrigue, an unsuccessful 12-part series about a detective working for industrial clients. And the Victorian policeman idea first made it to the screen in 1963, when ATV transmitted Sergeant Cork, starring John Barrie.
It does not actually matter that they have been on before - indeed, it may even be an advantage. Because if you look closely at the history of crime fiction on television, it soon becomes clear that the best metaphor for the way new programmes are introduced to the schedules is crop rotation, a calculated husbandry of the audience's capacity to get excited. As the yield from one style of police drama begins to fall away, writers and directors move on to plough a different field. A period dominated by thick- ear, wheel-squealing dramas such as The Sweeney (almost immediately imitated by the BBC's Target) will be followed by a fashion for oddball detectives, for loners and outsiders. There are very few new ideas - just the dependable amnesia of the audience and the dependable satisfactions of the old genres.
It is risky to draw large conclusions from these swirls of fashion. It might be tempting to see the social history of post-war Britain reflected in the growing cynicism of police drama, in its rough progression from ingenuous admiration to suspicion and cynicism, but the chronology is never quite so obliging or one-directional. It is clearly true that we have come a long way from Fabian of Scotland Yard (first broadcast in 1954) to get to the sardonic ambiguities of Between the Lines but, in truth, it is a journey that has been made before. Z-Cars shocked its first viewers by the grittiness of its characterisation - its policemen drank, got things wrong, even beat their wives - but, for all its transforming realism, Z-Cars did not rule out a return to the reassuring innocence of Heartbeat, a Nineties show with a Sixties setting and mentality to match. Dixon of Dock Green, the very epitome of consolatory police drama, actually overlapped for a time with The Sweeney, a conjunction that now seems unthinkable.
The signs are that the pendulum is swinging back again, to a simpler, far less agonised style. Carlton's The Thieftakers, a recent pilot for a new Flying Squad series, actually concluded with the words "You're nicked", a cheeky homage to the clich that had come to sum up the shortcomings of its famous predecessor. There is a mood of considered nostalgia at the BBC as well. Far from believing that there were too many police dramas, Nick Elliott, head of drama series at the BBC, was sure there were too few when he first arrived, charged with recapturing the mainstream audience for the corporation. "There had been an awful lot of police shows at ITV, but there was nothing here really,'' he says. "In terms of a mainstream police series, I don't think there were any at the BBC." In his view, the fields had lain fallow for too long and the time was right for a return to some of the traditional formats - "men jumping out of vans" in the industry shorthand. Jo Wright, producer of Out of the Blue, a police procedural series due from the BBC next month, makes the same point. "When people say `Not another cop show' it makes me laugh because there are very few and the BBC hasn't had one for a long time ... There have been loads of detectives but not an ensemble police show."
Such technicalities are unlikely to console those, like the writer Andrew Davies, who see crime fiction as having television executives in an imaginative armlock. For Davies, the frenzied quest for a new angle, the attempt to flog the old forms into a semblance of novelty, is a tragic waste of airtime. It is easy to see what he means - the increasingly desperate attempts to refresh the private eye format brought little to the screen but a Cook's tour of ethnic minorities, British provinces and odd jobs. We were given black detectives, Chinese detectives, disc jockey detectives, Jewish detectives, cute girl detectives, little old lady detectives and restaurateur detectives. What next, one wondered? An Inuit detective, using his peerless knowledge of snow conditions to track down London criminals?
But Davies is wrong to think this is in any way a recent development - and almost certainly helpless in the face of the enduring appeal of crime fiction for a popular audience. He should, perhaps, thank his lucky stars that British television is as restrained as it is. In 1973, the peak of the American boom in crime series, such material accounted for 13 out of the season's 24 new shows and more than a third of prime-time viewing. The fact that America recovered from this addiction fairly rapidly may give him modest cause for optimism.
Besides, the disappearance of police fiction altogether is unthinkable, and not simply because it has always been central to all forms of mass entertainment, not just television. Crime fiction satisfies in us a secret yearning for justice, the unappeasable appetite for a fair world, which begins in childhood and never leaves us. It satisfies our need for conclusions, both moral and narrative. The earliest police fiction supplied this in the least sophisticated form - a world in which crime was reduced to a set of case histories, each satisfactorily sealed, without loose ends. "Crime, detection and arrest tends to provide a dramatic structure," Nick Elliott points out, "and there's a moral dimension to it. Basically you're on their side and basically they're on the side of good and against evil."
This remains true in even the most disenchanted police series. Successful cop shows are never truly cynical. The characters may wear a carapace of cynicism, may even drift outside the letter of the law, but we recognise it as their armour against the disappointments of human justice. They always, finally, care how the story ends, either serving as representatives of our own frustration or deliverers of an approximate retribution.
Moreover, the very familiarity of crime drama only increases its grip on the schedules. Commissioning editors anxious to increase their audience figures know that it provides the imaginative equivalent of a pre-sale, a familiar format in which viewers will rapidly find their feet. They do not have to worry about the genre, only this particular manifestation of it. And there are opportunities for writers, too. "The opening episode doesn't have to set up the procedure," explains Jo Wright. "It's very liberating, particularly with a character-based show like ours because you don't have to keep telling the audience what they do."
This suggests that good writers might do better to bend the the genre to their own ends rather than protest ineffectively about its predominance. Police series will continue to be a pillar of the schedules and history suggests that the same old formats will take their turn in the rota of fashion. But that is not necessarily a cause for creative despair. Sometimes the execution matters more than the form. As Cracker and Between the Lines triumphantly demonstrated, something that looks reassuringly like a conventional crime fiction can actually deliver something quite different. What appeared to be a hollow convention turns out to be a Trojan horse in the living room.