The criminal justice system is putting more people at risk by failing to tackle potential serial rapists, the victims’ commissioner has warned.

Dame Vera Baird expressed the concerns as official figures showed that reports of rape are rising but the number of charges being brought has fallen.

Rapes reported to police rose by almost 13,000 to 54,045 in 2017-18, compared with 41,186 the previous year, with 11,913 attacks not recorded as crimes, up from 8,624.

The overall charge rate fell from 6.8% to 4.2%, according to data recorded by public bodies, gathered by the Rape Monitoring Group and published by HM Inspectorate of Constabulary.

Baird said the government needed to act quickly in its review of how complaints were handled to make sure victims received justice: “The criminal justice system is letting down current victims and creating new victims by failing to tackle potential serial rapists.”

Only one in every 50 cases results in a conviction. How can this be justice? Vera Baird

She added: “More complainants are coming forward, but fewer cases are being prosecuted and only one in every 50 cases results in a conviction. How can this be justice? We know that nearly four in five victims of sexual assault choose not to report the crimes committed against them. How can we ever give these victims the confidence to report when so few cases ever secure a conviction?

“We need to understand the reasons behind this failure. It is in part down to the treatment of complainants by police and prosecutors – for example, failing to update them on investigations or making intrusive and disproportionate demands on their personal data. We also know that the treatment of complainants in the courtroom can cause trauma and distress.”

The data was recorded by bodies including the Home Office, the Office for National Statistics, the Crown Prosecution Service (CPS) and the Ministry of Justice (MoJ), covering all 43 police forces in England and Wales and the British Transport Police. It was previously published separately.

The CPS decided not to charge any suspects in just under half the cases. For 24,280 of the offences there were “evidential difficulties”, such as the victim not supporting a prosecution. There were 2,238 offences that resulted in a charge or summons, with the outcome for 6,647 not yet recorded.

According to the latest MoJ figures, the average prison sentence for rape is about nine years.

Rebecca Hitchen, campaigns manager at the End Violence Against Women Coalition, said the figures were “truly shocking” and evidence of “just how broken the system is”.

She added: “This is a crisis and it needs the highest level of political attention. We urge the prime minister, the home secretary and the justice secretary to get fully involved in the ongoing rape review, from which very little has been heard. We urge them to demand answers as to what is going on. They should also make clear, public reassurances to women, and men, who are considering reporting rape, that meaningful work will be done to improve access to justice.”

A CPS spokesman said: “The growing gap between the number of rapes recorded and the number of cases going to court is a great cause of concern. That’s why the CPS is taking part in a system-wide review to scrutinise how these cases are being handled.” He added that the “significant fall in the volume of referrals from the police” had contributed to the drop in rape charges.

Wendy Williams, an inspector of constabulary, said it was vital that statistics about rape were made as transparent as possible and she hoped the data would help the criminal justice system do all it could to “prevent this most heinous of crimes”.