A sex-obsessed chef has been jailed for at least 34 years for the murder of aspiring model Sally Anne Bowman.

Mark Dixie, 37, has been given a life sentence for killing the 18-year-old outside her home in Croydon, south London. He had denied the murder but was convicted by a jury at the Old Bailey after just three-and-a-half hours of deliberations.

Sally Anne's partially naked body was left in a pool of blood in her driveway in September 2005. She had been subjected to a gruesome sexual attack when she was dead or dying from seven stab wounds.

Father-of-three Dixie, who had an obsession with violent sex, claimed he found the teenager, thought she had passed out drunk and had sex with her. He told the jury he did not realise she was dead until after he had sex with her.

Dixie had a string of previous convictions for sex offences and detectives believe he may have killed while living in Australia in the 1990s.

He was brought to justice for Sally Anne's murder by chance when he was arrested nine months later after getting into a minor scuffle over a World Cup football match at Ye Olde Six Bells pub in Horley, Surrey, where he was working.

His DNA was taken and matched to the murder when it was put on the police national computer 12 days later.

Detective Superintendent Stuart Cundy, who led the investigation, said his personal opinion was that a national DNA database would have led to Dixie's arrest within 24 hours. Speaking outside court, he said Dixie's defence was "truly contemptible".

"This is a man who has put people through a tremendous ordeal of anguish and distress. He must now face the consequences of those actions."

On the day of the murder, Dixie had been staying overnight with friends in a flat near to Sally Anne's home after spending a drug and booze-filled day celebrating his 35th birthday.

He went on the prowl after the two women went to bed at 2.30am - locking themselves in a bedroom.

Some 400 yards from Blenheim Crescent, where he used to live, he is thought to have attacked a woman motorist whose mobile phone was stolen before a taxi driver came to her aid.

Forty minutes later, neighbours heard Sally Anne's screams at 4.20am. One saw Dixie walking around but could not see the body in the dark.

It is thought Dixie had been lying in wait after seeing the teenager arguing with her boyfriend Lewis Sproston. He dropped her off around 4.10am to the "comparative safety" of her driveway.

After Dixie cut an artery in her neck, Sally Anne quickly collapsed as blood flowed from her body. On the ground, Dixie stabbed her again in the neck and body - so hard that the knife came through the other side.

He then rolled her skirt up and her top down before defiling her body. He placed bits of cement rubble into her mouth. Dixie took the teenager's underwear and her bag containing her mobile phone and make-up as trophies.

Back at the friends' flat in Avondale Road, Dixie got back on the sofa and watched television, finishing off a cannabis joint.

Det Supt Cundy said: "Dixie is a very sexually active man. That night he definitely wanted it."

After the verdict, Sally Anne's father Paul Bowman said: "The last two-and-a-half years have been torturously painful and immensely difficult and I do not think we could have got through it without the love and support that has been hugely available from family and friends.

"I hope that now Sally Anne can rest in peace and those affected so deeply by her untimely and brutal death can be afforded at least the chance to begin to grieve in earnest."

He then sent a message to his daughter: "Sally Anne, you may have been taken from us, but rest assured, you will forever be missed and never forgotten."

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