DETECTIVES are making fresh appeals in connection with a shocking rape that took place in Harrogate a year ago this weekend.

They are especially anxious to trace a mystery caller who may hold the key to the assault, which took place in Ripon Road close to the town centre in the early hours of Saturday, July 3.

Officers are targeting club-goers and delegates to this year's Ambex International conference and exhibition - the same event that was in progress a year ago when a local woman was attacked. She had been dropped off in the town by the courtesy bus from the Harrogate Arms and was walking home at about 2.30am when a middle-aged man dragged her into undergrowth opposite Springfield Avenue. He subjected her to a sexual assault lasting more than an hour and a half.

Detective Chief Inspector Javid Ali, head of Western Area CID said: "The file remains open and under active investigation. This man committed an horrific attack and must be brought to justice."

The victim described her attacker as being white, between 40 and 60 years old, with grey curly hair. He had a Yorkshire accent. On the night of the rape he was wearing blue jeans and a black T-shirt with a motif on the front.

His victim is in her 20s, 5ft 2in tall, with blonde hair. She was wearing jeans and a dark blue fleece on the night of the attack.

Det Chief Insp Ali said: "We are making this new appeal on the anniversary of the attack. It may well be that some residents and - especially summer visitors were not aware of the assault at the time."

Harrogate detectives have prepared posters and leaflets, which they are distributing around the town centre, especially in hotels and in clubs. They will be approaching delegates to Ambex, which is a major conference and exhibition attracting representatives of ambulance services from all over Britain and beyond.

Det Chief Insp Ali said: "I believe that someone, somewhere knows who this man is - or at least has strong suspicions about a friend or colleague.

"In our experience allegiances change, particularly after the passing of time allows people to reflect on whether or not they really want to shield a man like this. This may be the time for someone to come forward with the piece of information that we so badly need."

One person detectives are particularly anxious to speak to is a woman who phoned a few days after the assault. Det Chief Insp Ali said: "She said she had some information for us and she spoke of the Springfield area, which is near the attack scene. We felt she was a genuine caller and an officer made an appointment to meet her; the lady did not turn up.

"I am asking that lady to contact us again, anonymously if she prefers."

Anyone who can help should telephone the Police Help Desk on 01423 505541. All calls will be dealt with in confidence.