Rape attacks are increasing rapidly nationwide but according to the latest Home Office figures the number of cases resulting in prosecution has fallen to a record low.

And as a result Cheshire Constabulary is taking steps to provide guidance to victims on how the crime is investigated.

The four-part process will be explained step-by-step in the Guardian during the forthcoming weeks and this second article focuses on the role of forensic and medical evidence and the prosecution of an offender through the courts.

Police investigate offences of rape but the Crown Prosecution Service (CPS) is responsible for deciding, by reviewing the evidence available and assessing whether the matter is in the public interest, if an offender can be prosecuted. It also plays a vital role in supporting the victim through the court process as well as ensuring the defendant's right to a fair trial is adhered to.

Kate Hurst, rape case coordinator for Cheshire CPS, said specialist prosecutors have a key part in the investigation process.

She said: "The benefit of having specialist prosecutors is that only those lawyers who have particular expertise and the right skills in handling cases of this nature will be responsible for them.

"This expertise is gained from extensive experience and training and it is hoped this consistent approach is ultimately reflected in successful outcomes and increased support for victims and witnesses."

Police will seek to find corroborating forensic or medical evidence should a prosecution go ahead but, although this is not essential, if a jury cannot decide between the accounts of the victim and defendant, a case may collapse.

The victim is usually required to give courtroom evidence unless the offender pleads guilty but support will be provided by the Witness Service and special measures such as providing evidence by video link can be used depending on the individual merits of each case.

Kate said: "In situations where the victim is not automatically entitled to be video interviewed, it is possible for them to give evidence by TV link from another room without having to enter the court room.

"A member of the Witness Service can also be present to act as support for the victim whilst they give evidence."

But Kate is keen to stress a case not proceeding to court is not because a victim's account is doubted.

Kate said: "If the CPS is not satisfied a jury could convict a defendant by finding them guilty beyond reasonable doubt that's when cases do not go ahead.

"A common difficulty is it's often one person's word against another when the issue is one of consent and there is no supporting medical or forensic evidence.

"This is why it's important for victims to come forward to the police straightaway to make sure all available evidence can be secured.

Next week's article examines the support available to victims.

Anyone with any information about crime, should call Cheshire Police in 0845 458 0000 or Crimestoppers free and anonymously on 0800 5551111.