Devon and Cornwall Police is working with prosecutors to try to increase the proportion of rape cases sent for trial.

The force wants to increase its rate of referrals to the Crown Prosecution Service without reducing the conviction rate – the second highest in the country.

Details emerged in a response by the force to a claim victims faced a national “postcode lottery” for cases being sent to prosecutors.

Research carried out by a news website showed Devon and Cornwall referred only around one in 20 cases to the Crown Prosecution Service in 2017/18. The figure of 4.7 per cent was less than half the national average.

Details obtained by The Independent showed the rate of cases sent for a charging decision was 5.2 per cent in Kent and 6.3 per cent in West Yorkshire. In South Wales and Norfolk it was 20 per cent, compared to the national average of 11.7 per cent.

The website reported Victims Commissioner Dame Vera Baird saying the variation was “vast and worrying” and suggested the prospect of getting justice was a “postcode lottery”.

Devon and Cornwall Police said decision-making on rape cases took into account a wide range of factors beyond the single objective of obtaining a conviction.

They could include “considerations around safeguarding, providing the appropriate support and respecting the wishes of the victim”.

A statement from the force said it was “victim-led” and it had the second highest conviction rate for cases that went to court at 51.7 per cent.

It acknowledged the low referral rate and said it was working with the CPS in line with the national direction to try to increase the number of cases sent to prosecutors without reducing the number of successful convictions.

The region’s Police and Crime Commissioner Alison Hernandez said there was evidence that more victims were coming forward and services had improved.

She said she was concerned about the conviction rate and has commissioned a review into how rape cases are handled and the support for victims.

Figures for the first quarter of this year show a big rise in cases handled by the three specialist Sexual Assault Referral Centres in Truro, Exeter and Plymouth.

The force said the physical and psychological consequences of serious sexual assaults were likely to be “profound, wide-ranging and complex” and it was committed to providing the highest levels of service to victims.

The statement on behalf of the Devon and Cornwall and Dorset forces said: “We acknowledge that the CPS referral rates are low and we are working to understand the impact of this on the service we offer victims.

“However, an increase in referral rates should not in itself be seen as an indication of an improvement in quality of investigations.

“Our focus is to ensure that offences which meet the referral threshold are identified and passed on for decision or advice, rather than causing further stress to the already stretched system by making inappropriate referrals.

“There are huge challenges around the investigation of sexual offences and both forces are committed to working with partners to ensure the best possible outcomes for all victims.”

PCC Alison Hernandez said: “It is absolutely vital that victims of rape feel confident that they can report their crimes in the knowledge that they will be treated with respect and dignity and there is a realistic chance that the perpetrator will be brought to justice.

“My office has worked closely with the NHS to improve services for victims of sexual offences, with the opening of a new Sexual Assault Referral Centre in Plymouth in December 2018 to complement those in Truro and Exeter.

“These centres provide a safe haven for victims where they can receive support, medical care and forensic examination in one place.

“We also commission an Independent Sexual Violence Advisor service (ISVA) for victims in the south west.

“ISVAs are trained to provide emotional and practical support to survivors of rape, sexual abuse and sexual assault who have reported to the police or are considering reporting to the police.

“While there is some evidence to suggest that more victims of these horrendous crimes are feeling more confident in coming forward, and services for victims have improved significantly, I remain concerned about the conviction rate and will be urging our courts and police force to work together to improve it.

“In order to better understand the complexities around how these cases are handled and the support that is on hand for victims I have commissioned a substantive independent review into the subject.

“That report is being finalised and will be made public once completed, along with plans to deliver improvements in the area.”

The National Police Chiefs’ Council lead for adult sexual offences and rape, Avon & Somerset’s Deputy Chief Constable Sarah Crew, said forces had made it easier for victims to report crimes.

She said: “Rape and sexual assault cases are some of the most complex crimes that police deal with.

“We’ve made it easier for victims to report in the way they feel most comfortable.

“Many more victims now have the confidence to come forward and report their experiences to us, in addition to receiving crucial access to support services.”

The Office of the Police and Crime Commissioner commissions the Victim Care Network which provides help and advice to victims of all crimes, whether reported or not. Victims can contact the network on 01392 475900 or via its website at victimcaredevonandcornwall.org.uk