It was about midnight when Doris Day lookalike Lorraine Benson, 22, stepped off the train at Raynes Park station, south London. This was five days before Christmas, 1988, and the place was cold, dark and deserted.

Lorraine, a children’s photographer, had been to a Christmas party in Clapham. She was expecting to be met, but her friend wasn’t there, so she set off alone into the darkness.

She hadn’t gone very far when a fist came out of the night, stunning her. As she was frog-marched to a footpath off Cottenham Park Road she screamed, but no one came to her rescue.

Her attacker ripped off her clothes, battered her, and tried unsuccessfully to rape her – unsuccessfully, because she fought like a tigress. Her last words as he wound a three-foot length of rope around her neck were “Please don’t kill me.”

Lorraine’s body was found next day hidden under brambles and leaves. Nearby was a man’s handkerchief, bearing evidence that the owner was suffering from a heavy cold.

A trawl through known sex offenders in the area revealed John Dunne, a 20-year-old tubby six-footer. Dunne went to prison for rape when he was 15. When he was released reports warned that he would strike again. And he did. Two months before killing Lorraine he was arrested in connection with another rape.

On the night Lorraine died, Dunne, of Amity Grove, Wimbledon, had a heavy cold. Forensic evidence, including bite marks he had made on Lorraine’s arm, built up an overwhelming case against him.

“I must be bloody thick,” he confessed as he told how he had swallowed purple heart tablets and drunk cider, rum and whisky before setting out to find a woman – any woman – to rape.

At the Old Bailey on OCTOBER 23rd, 1989, Dunne pleaded guilty to murder and was sentenced to life. The judge told him: “You must not be released until you no longer constitute a danger to women. If that means you will be detained for the rest of your life, so be it.”