Some remarkable detective work has put a serial rapist behind bars 14 years after he carried out a horrendous' sex attack in a Brent Cross alleyway.

Gary Baldrey, 47, an illegal immigrant who has four previous convictions for rape in his native Zimbabwe, was linked to the crime years after committing it thanks to DNA testing carried out by the Metropolitan Police's Operation Sapphire Cold Case Team.

Now wheelchair-bound, Baldrey, of Goodyear House, Oak Lane, East Finchley, undergoes dialysis after hepatitis destroyed his kidneys and is expected to die while serving his five-year sentence.

He was arrested in July when he went for treatment at the Royal Free Hospital. Scientific advances in DNA analysis meant the tiniest traces of semen and blood found on the victim's clothes were matched.

Baldrey, who also goes by the alias Malcolm Ashford, pleaded guilty to rape on Thursday. Snaresbrook Crown Court heard how he subjected his 23-year-old Australian victim to a terrifying' knife-point attack. Sandy Canavan, prosecuting, said Baldrey pounced on her on October 3, 1990, when she was returning home from the West End after a night at the theatre with friends. She took a short cut near to Claremont Road, Brent Cross, at about 12.20am.

"She was about 120 yards down the alley when the defendant jumped down from a wire fence on her left-hand side," the prosecutor said. "She started screaming, so he stood in front of her so they were face to face then grabbed hold of her left arm. She started screaming and struggling so he put a knife to the right-hand side of her face."

Baldrey told her to stop screaming and threatened to stab her. She begged him to take her money but he ordered her to get down under the wire fence and started groping her breast before telling her to take her pants off.

Afterwards, before he dashed off, he told her: "Run fast, you bitch."

The court heard how Baldrey has a string of convictions for sex attacks. In 1975 in Zimbabwe, he raped a woman at her home after threatening her with a knife and tying her to a bed with her stockings. He was ordered to serve just nine months in jail. In 1976, he was sentenced to 18 months, suspended for five years, for two attempted rapes in Zimbabwe, and in January 1981 he was jailed for five years for raping another woman whom he threatened with a bread knife.

Two other charges of attempted rape and one of indecent assault, which he denied, were ordered to lie on file.

Detective Constable Andy Lawrence said: "This investigation demonstrates the ongoing commitment by the Sapphire Cold Case Team to identify and prosecute the perpetrators of these horrific crimes.

"We would also appeal to anyone who believes they may well have been attacked by Baldrey in the Golders Green area to contact us on either 020 7321 9084 or call Crimestoppers on 0800 555 111."