A teenage schoolgirl was brutally raped and strangled by a builder who forced his way into her home and overpowered her after a violent struggle -in a case which has remained unsolved for “half-a-lifetime,” a court heard.

Tiler James Warnock, 56, is standing trial at the Old Bailey 33 years after Yiannoulla Yianni’s lifeless body was found by her parents lying half naked on their bed at the family home in South Hampstead.

The prosecution allege that after barging in, Warnock, then 22, had chased the terrified 17-year-old upstairs and kicked down the door of a bedroom where she was hiding before raping her and suffocating her “probably by holding her neck in an armlock.”

The jury heard that the teenage virgin, who in the “traditional Greek manner” was not allowed to leave the house without a chaperone, had visited her parents in their shoe repair shop Nick’s around the corner from the family’s Belsize Road home.

She had returned home at around just ahead of her parents to prepare the family evening meal and was listening to music and boiling the kettle, when there was a knock on the door at around 2pm on August 13 1982.

Crispin Aylett QC, prosecuting, said: “Yiannoulla went downstairs and opened the door to a stranger. He forced his way in and chased her up the stairs. He then attacked her, overpowered her and raped her before going on to murder her.”

Witnesses reported seeing her laughing and chatting with a man on the doorstep.

Neighbours described hearing an argument and a scream before everything went quiet.

When Yiannoulla’s parents George and Elli Yianni came home to join her half an hour later they found their daughter’s jewellery and belongings scattered on the stairs.

Mr Aylett said: “Looking for her, they went into their bedroom and were met with a sight beyond their worst imagining. Their beloved daughter was lying on their bed, She was obviously dead.

“Yiannoulla was naked from the waist down, her skirt had been rolled up to her waist, her blouse and her bra had been cut open and there were reddish marks around her neck,” he said.

He told the jury: “As might be expected, Mr and Mrs Yianni were hysterical with the shock and grief.”

Police who responded to their call found Mrs Yianni “lying on the floor, screaming and shouting, crying and pulling at her hair,” he said.

Officers interviewed thousands of people who came forward after reports in the national and local press and a TV reconstruction of events, but police were never able to identify the killer.

Mr Aylett said: “This terrible crime has remained unsolved for half-a-lifetime.”

Although there was “no such thing as DNA evidence back in 1982”, the prosecutor explained that with new technology, in 2001 a DNA profile was obtained from semen samples at the scene.

With no matches on their database however the police were no further forward and the case remained unsolved - until just after last Christmas.

Mr Aylett said: “The police came into possession of the defendant’s DNA profile. His profile was then entered into the database. The semen was his.”

His fingerprints also matched those found around a bathtub at the scene, the jury heard.

Warnock, who lived nearby in Adelaide Road at the time of the murder and was working as a tiler on houses around the corner, told police after his arrest that he had struck up a friendship with Yiannoulla after meeting her in her father’s shop.

Describing himself as a “John Travolta lookalike” who was “successful with the ladies,” he told police he had started a relationship with her and they had sex about ten times at the Yianni’s family home.

Mr Aylett said Warnock told police “they had sex in her bedroom. He remembered that she had always been anxious lest her parents come home and find them together.”

“The prosecution allege that, faced with overwhelming evidence that he was the murderer of Yiannoulla Yianni, the defendant has simply come up with a story. For a number of different reasons, this story simply does not bear scrutiny,” Mr Aylett added.

Yiannoulla, who had a Saturday job in Woolworths in Finchley Road, had just left Quintin Kynaston School, in Marlborough HIll, and was waiting for O Level results when she was murdered. She was hoping to gain a place on a beautician’s course at West End College.

She came from a large, closeknit Greek family with an older sister Maria, older brother Ricky and younger brother Peter.

Her sister said her parents were very protective “making it virtually impossible for her to have a boyfriend.”

“Nevertheless, Yiannoulla was an attractive, physically mature young woman who looked older than she really was,” said Mr Aylett.

Jurors heard Warnock, who is of heavy build with grey hair and a beard, had married wife Lynne a year before the murder. The couple, who lived in the Taplow flats, in Adelaide Road, went on to have two sons now in their 30s, and divorced in 2003.

Warnock, of Harrington Street, Camden, denies a charge of rape and another of murder.

The trial continues.