The reforms, being tested in six pilot projects, were intended to reduce the time between suspects being charged and their first court appearance, but have had the unintended effect of reducing the number of cases by 1,252.
Before the pilot schemes were introduced, police were bringing 4,000 charges a year, but the figure fell to 2,748 last year, said a report, by accountants Erst & Young.
Professor Lee Bridges of Warwick University, who was asked by the Lord Chancellor, Lord Irvine of Lairg, to conduct separate research into the reforms earlier this year, said police forces in the pilot areas were dropping, or not bringing charges because of the new administrative burden. Under the Narey reforms, police officers are asked to prepare cases in days rather than weeks.
Professor Bridges, whose own report claimed the reforms would lead to injustice for defendants, said that police forces were having to commit more resources to administration. This, he said, meant less time for charging more people.
While the report by Ernst & Young considered some of the possible consequences of the shortfall, it did not look at why the numbers had declined.
Despite the Ernst & Young report, the Home Office is pressing ahead with the reforms, many of which were contained in the Crime and Disorder Act passed last year, and will roll out more pilot schemes nationally from 1 November this year.
Professor Bridges said that it was "madness" to press ahead with the pilots when reports by Ernst & Young and the Crown Prosecution Service Inspectorate both urged careful planning.
"It risks not only some of the supposed benefits but a number of unintended consequences, one of which will be a considerable reduction in the number of people being charged," he said.
His own report found that some cases were "unnecessarily" going to the Crown Court and more people were pleading not guilty.
In July last year, Mr Straw approved nearly all of the 33 recommendations made by Martin Nary, a senior civil servant, who had been asked to look at ways of reducing delay in the criminal justice system.
But the Warwick University report, based on interviews with defence solicitors, found that the role of the police station as a place where "active defence work" is carried out would become more significant under the reforms. The solicitors interviewed were also concerned about the use of Crown Prosecution Service lawyers at the police station. The lawyers questioned thought this might lead to a "serious erosion of the independence of the CPS."Reuse content