Abdalla Yones, 48, killed his daughter Heshu, 16, and then tried to take his own life after she had planned to run away from home after starting a relationship with a Lebanese Christian boy.

Investigating detectives said it was one of the most tragic cases they ever had to deal with.

Yones asked to be executed for what he called his "appalling" crime, but Judge Neil Denison told him that he had no such power.

Yones was the first person to plead guilty to murder in a so-called “honour killing” case because he perceived that her relationship with a non-Muslim brought shame on the family.

Police believe there were 12 such killings in Britain last year, including six in London, and have vowed to investigate other members of the community who may have colluded to help cover up the death.

Judge Neil Denison said today at the Old Bailey before jailing Yones: "This is, in any view, a tragic story arising out of irreconcilable cultural differences between traditional Kurdish values and the values of western society".

Heshu's body was found in the bloodstained bathroom of the family home in Acton, West London, on October 12 last year. A kitchen knife was protruding from her neck and was bent out of shape.

The court was told that Yones then tried and failed to take his own life after killing his daughter. He slashed his wrist and jumped from a 25-foot balcony. He was later hospitalised for four months.

Heshu, a schoolgirl at the William Morris academy in Fulham, west London, was a "bubbly, cheeky, fun-loving girl, popular at school and with her friends," according to John McGuinness QC, prosecuting.

"Her father, a strict Muslim, did not approve of her western lifestyle. She wanted to be with her friends and use a mobile phone quite often.

"There was tension at home particularly with her father. He was not happy with her lifestyle and wanted her to live within the Muslim religion and cultural traditions."

Heshu had plans to run away from home just days before her father killed her. Letters produced in court indicated that she had been the victim of domestic violence by her father.

"Hey, for an older man you have a good strong punch and kick. I hope you enjoyed testing your strength on me, it was fun being on the receiving end. Well done," one letter said.

She began a sexual relationship with her boyfriend who she had met at school.

Sexual relationships before marriage were strictly forbidden under Muslim law especially with someone outside the religion, said Mr McGuinness.

The court was told that Yones was given political asylum in Britain when he arrived from Kurdistan ten years ago, but found it difficult to adjust to western life.

He had been the victim of a gas attack and his family and many of their friends had suffered greatly at the hands of Saddam Hussein, the court was told.

Judge Denison told Yones: "It is plain you strongly and genuinely disapproved of the lifestyle in this country of your daughter and the fact that was affecting her schoolwork.

"But having said that, the killing and the manner of it was, as you have recognised, an appalling act. That is why immediately after and then again last month, you tried to take your own life. I accept that is still your intention.

"But there is only one sentence that the law allows me to pass where the crime is murder and that is the sentence I do pass - life."

Detective Inspector Brent Hyatt, from the Metropolitan Police, said: "There was no excuse or even rational reason for this. It is one of the most tragic cases I have ever dealt with".