The squad is 112 detectives below strength because not enough good officers have applied for jobs. As a result the unit, which has 1,450 officers, will underspend on its budget this year by pounds 3.7m.
Lack of investment in CID units by chief constables, a series of corruption scandals and limited career prospects for detectives are all seen as factors in turning officers away from plain-clothes work.
Last night a spokesman for the National Crime Squad said regional police forces are reluctant to release their best officers to the unit: "It's a problem. We are competing in a limited market and good detectives are hard to come by. We will not compromise our standards."
Ambitious uniformed officers are not joining CID units because being a detective is no longer regarded as the best path to promotion. Many senior officers, including most of the highest ranks at Scotland Yard, have not worked as detectives.
Gary Mason, the editor of Police Review, said that when chief constables look for potential management material they are less likely to choose officers with "hardened CID experience but who are not necessarily so good at interpersonal skills and media relations".
Other officers have been driven from CID by the "tenure" system which demands they return to uniform after a given period, and by a series of corruption scandals which have rocked confidence in what was once the most prestigious branch of the police service.
The Independent reported last July that a national database of retired detectives was being set up because of a national shortage of murder detectives, in a scheme supported by the Association of Chief Police Officers (Acpo).
Tony Rogers, chairman of Acpo's homicide working group and the Assistant Chief Constable of South Wales, who will be selecting candidates, said chief officers were partly to blame for the shortage of experienced detectives. The shortfall was "largely because senior police officers of Acpo rank have marginalised the CID and killed off the breeding-grounds for future investigators," he said.
Mr Rogers said some police chiefs were frightened of handling CID departments and fearful of tackling allegations of corruption or bad practice. He called the approach "CID leprosy". He added: "They simply throw the baby out with the bath water. The shortage of senior investigators is a widespread national problem."
The problems are likely to be made worse by demands that officers submit their bank accounts for scrutiny.Reuse content