A specialist centre for rape victims is to open this year to help police bring more sex offenders to justice.

Only a tiny proportion of rape investigations end with a successful prosecution in Sussex.

Police believe the better care and organisation available at the new Sexual Assault Referral Centre in Crawley will give victims the support they have lacked in the past.

Victims of sexual assaults from all over Sussex will be taken to the secure centre at Crawley Hospital from July where they will have access to healthcare support and trained police staff.

The centre will be manned 24 hours a day by a team of forensic doctors and nurses trained to gather evidence for police as well as caring for patients.

Officers believe the centre will offer better care for victims, giving them the confidence to take their case on through the court system.

Victims will be able to go directly to the centre if they wish and will still be able to access the services even if they do not wish to co-operate with an investigation.

Detective Superintendent Graham Bartlett, the head of Sussex Police's specialist investigations unit, said: "What has been seen in other parts of the country is the quality of service given to the victims is so high people feel happier to remain engaged in the criminal justice system."

It is also hoped the centre will allow police to gather crucial evidence they can use later to convict the culprits.

National research shows more than a third of prosecutions are dropped due to a lack of evidence, despite most incidents being reported within 24 hours.

Rape campaigners say many investigations are dropped because the victim decides not to press on with their complaint.

They believe specialist care from the outset can encourage victims to be more confident in the system.

There are 20 sexual assault referral centres in the country at the moment, with plans for another 18.

In the south east centres are already open in London, Portsmouth, Kent and Swindon.

In 2005 Sussex had the seventh lowest conviction rate in the country, at 3.35 per cent.

Ben Duncan, Green councillor for the Queens Park area of Brighton, said: "Sussex has for many years had one of the worst conviction rates in the entire country.

"One of the reasons for that has been a dearth of crisis centres for victims of rape and sexual assaults."

Coun Duncan, who is a member of Sussex Police Authority, said the recent opening of a Life Centre in Brighton was a positive sign that victims were beginning to get better resources within their own areas.

He backed Sussex Police's plan for the new referral centre in Crawley.

He said: "If the new centre creates a safe space for victims to report what is happening and it leads to an increase in detection rates that can only be good news."

Supt Bartlett said the main difficulty in securing convictions is proving that sex took place without consent.

He said: "Rape is an offence that mostly has no or very few independent witnesses.

"Often it comes down to one person's word against another's.

"There are lots of ways we can investigate the issue of consent.

"If you don't have the confidence of the victim you can't rebut any claim of consent the defendant makes."

The new centre in Crawley, which will also host a project for domestic violence victims, is being developed in partnership with West Sussex County Council.