This was revealed last week by one of Britain's senior policemen, Detective Superintendent Bob Taylor, who tomorrow takes over as co-ordinator of the Regional Crime Squad North East, a 253-strong squad tasked with investigating major crimes and targeting major criminals in an area extending from Derby to the Scottish border.
"Detectives these days," says Det Supt Taylor, "have become suburbanites. When they stop work at night they go back to their Barrett homes on some leafy, out-of-town estate. Times have changed."
Not so long ago, police officers in Britain lived in police houses. It was a matter of domestic economics, as many officers, certainly those in the lower ranks, did not earn enough to consider buying their own homes. The steady climb of police pay levels in the past 15 years has changed that.
The rising affluence which has swept officers out of the cities and into suburbs has, however, meant that they no longer live cheek-by-jowl with criminals, and as a result the paid informant, the "grass", has become a rare and threatened species.
It is a deficiency to which Det Supt Taylor feels he must give top priority, and he has let it be known that a substantial slice of his new squad's annual pounds 15m budget is to be set aside to build a network of informants.
Det Supt Taylor started his working life in his father's plumbing business and gained a law degree as he rose through police ranks. As a detective constable in Leeds 23 years ago, he thought nothing of spending three or four nights a week trailing round city pubs, rubbing shoulders with wrongdoers, and their relatives and friends, and building a rapport over pints. A detective knew it was part of the job; sometimes even an activity funded by the payment of overtime.
Not these days. Detectives are better educated, lead middle-class lives, and do not "live on the patch".
"The lads are not too keen on hanging around in the rougher pubs," he said. "In the world we now inhabit, if one villain knocks a policeman to the ground, another 12 will jump in to give him a kick.
"My lads want to get home to their wives and kids in their off-duty hours and I don't blame them. The police force doesn't encourage them to work in the old ways. And we don't pay them the overtime to do it any more.
"The fact is that most CID men have to live in outer suburbs for their own personal safety. These days you just can't expect them to live in the areas where they work because they'd be subject to intimidation."
Also, the law itself now demands that a distance be maintained between the detective and the villain with whom he has dealings. Twenty years ago, officers accompanied their charges to court, saw them sentenced and even had a drink with them afterwards if they were not jailed. The Police and Criminal Evidence Act now forbids a detective from entering the police station cell for the off-the-record chat which was once custom and practice. Most defendants turn up for interviews and questioning with a solicitor.
Hence the drive to recruit informants. Det Supt Taylor,a senior investigating officer with the West Yorkshire force for the past five years, has let it be known that he is ready to pay, and that to restore those lost relationships with the underworld there is serious money on offer - hundreds of thousands of pounds to buy high-quality information.
He talks of an incident that fixed his view. The trial of a gang of armed robbers was held up, expensively so, because one of the defendants had disappeared. As the hunt for the missing man went on, a well-known criminal presented himself. I can give you this man, he said, I can deliver him up on a plate, but I want pounds 5,000 - or forget it.
Det Supt Taylor had the authority to pay, but refused. Nine months later, after much tedious slog, the fugitive was arrested, in the place and the exact circumstances that the informer would have specified. The cost of the search operation: nearly pounds 40,000.
He now confesses: "Up till then I had a horror of handing out big money, public money, to villains. I thought it was immoral. But when it was all over I had time to think and the bitter truth dawned. I could have saved a lot of money and freed up six officers to work on other matters, clear up other crimes, for nine whole months, if I hadn't been so dogmatic."
Now he is going public with his offer, putting the underworld on notice that the market's about to lift.
He knows that some may find his announcement shocking, not least because outside London there remains a well-entrenched aversion to paying informants - "In some forces the payment of anything more than a fiver was a matter for the Chief Constable to decide. Some forces only set aside pounds 800 out of their total yearly budget for informants, while others went up to pounds 120,000. Yet informants are our vital source of intelligence."
One acting detective sergeant last week confirmed the cultural and social changes that have overtaken the police force. He joined the police after studying engineering at a provincial university, and now, after 10 years in the job, he lives with his wife in a country cottage, miles away from the run-down North-east port where he has worked under cover on drugs and robbery investigations.
"The police force is a damned good life," he said, "and the average detective can easily earn a more than respectable middle-class income.
"And it's undoubtedly true that all sorts of change has overtaken us and the criminals. The crooks are into drugs and themselves earning vast amounts of money. They no longer necessarily confine their activities to one part of one city. They have the money and the transport to take them anywhere they want to go.
"Equally, the average Regional Crime Squad detective can start work in Newcastle in the morning and find himself on surveillance in Brighton by the evening. It's not like in the Heartbeat scripts where the village bobby always nicks the villain in the village pub and always knows he must be the culprit because he drinks too much!
"Good informants are vital to much of our work. The trouble is, you don't recruit them in the local knitting circles. They cost money and they can be damned hard work and, quite frankly, disruptive of your private life. They always want to see you at the most inconvenient times, Sunday lunchtime or three o'clock in the morning or late on Saturday night.
"It has to be said that not every detective is exactly keen to recruit them in droves."
Det Supt Taylor's plan is not so much to buy in quantity as quality. But if his drive to restore communications is successful, he has already announced a willingness to spend even more money.
And having identified one cultural shift he'd be more then pleased to see another.
"We need to get away from the slightly guilty feeling that we are creeping round dark places dealing with slimy dirty people," he says. "It might be a good idea to delete the word informant from the police dictionary. Perhaps, henceforth, these people should be known simply as contacts or even community sources."