Only 37% of cases sent to CPS between April and September last year led to charges compared with 62% in 2013-14

Rape prosecutions in England and Wales have fallen to their lowest rate in more than five years, the Guardian can reveal.

Figures show just over a third of the 2,310 rape cases referred to the Crown Prosecution Service (CPS) between April and September last year resulted in charges being brought. The rate for the full year in 2013-14 was 62%.

The figures emerged six months after a Guardian investigation revealed the CPS in England and Wales has been quietly urged to take a more risk-averse approach in rape cases.

The furore over plummeting prosecution rates has prompted the Home Office to launch a comprehensive review of how rape cases are dealt with across the criminal justice system, as part of a package of measures to tackle violence against women and girls.

The Home Office said the review, launched on Wednesday, will specifically be tasked with investigating “why there have been reductions in volumes of police referrals, CPS charges, prosecutions and convictions for rape and serious sexual assault cases”.

The new figures reveal a growing proportion of cases have been “administratively finalised”, meaning suspects are not charged following a review of the case paperwork. Almost a quarter of all cases were administratively finalised in the first six months of 2018-19, compared with just 6% five years ago.

The proportion of cases that were administratively finalised doubled in the past year. The increase appears to have coincided with a change in policy whereby police are encouraged by the CPS to seek “early investigative advice” as to whether a prosecution would be likely to succeed at trial.

According to documents from the CPS, early investigative advice is intended to “ensure the early development of a joint strategy for the prosecution where they would benefit from CPS expertise and advice”.

“These new figures show once again that the justice system is not working for rape victims,” said the Independent Group MP Ann Coffey, who obtained the figures through a freedom of information request and shared them with the Guardian. “Fewer and fewer men accused of rape are being charged.”

The new figures also highlight a particular problem with charging rates in date and acquaintance rape cases. According to the data less than a third of young suspects, aged 18-24, in “rape only” cases, which exclude domestic and child abuse, are charged. That figure is down 11 percentage points on the previous full-year figures.

“We are extremely concerned that juries may be more inclined to make excuses for young adult male defendants because of ideas about what crosses the line and what a real rapist is,” said Sarah Green, co-director of End Violence Against Women. “This needs specific attention in the review.”

Green said the problem was exacerbated by police and prosecutors attempting to predict what a jury might think, creating a “feedback loop” that resulted in them failing to pursue certain cases.

“They are likely to drop cases or make poor decisions because they are second guessing the way juries are likely to behave,” she said.

Last year the Guardian reported prosecutors had been advised by the CPS to take a conservative approach to rape and serious sexual offence cases in an attempt to reduce low conviction rates.

Less than a third of rape prosecutions against men aged 18-24 resulted in a conviction, believed to be in part because of a reluctance by juries to brand young men as serious sex offenders at the start of their adult lives, as well as myths about the frequency of false rape allegations.

The CPS said early investigative advice meant more cases were being returned to the police for further investigation before a charging decision was made.

“We want to reassure anybody affected by rape that where there is sufficient evidence for us to prosecute, we will not hesitate to do so,” a spokesperson said.

“The increase in digital evidence means charging decisions are taking longer to complete. We now advise police at an earlier stage to build the strongest possible cases for prosecution. We can pass files back for further work but this does not necessarily mean the case is at an end.

“The review, announced today, will allow scrutiny of how these cases are handled across the justice system.”

Coffey said the Home Office review should examine whether the jury system remained the most appropriate system for rape and serious sexual offence cases.

“It is vital that this review thinks outside the box and examines whether the jury system is the best way to deliver justice in rape cases because of the dominance of ‘rape myths’ in society, such as girls who drink or wear short skirts are ‘asking for it’,” she said.