The father of British woman Lucie Blackman said his daughter had been robbed of justice today after a court cleared a Japanese businessman of involvement in her death.

Property developer Joji Obara, 54, was sentenced to life in prison after being convicted of a series of rapes and the death of an Australian woman.

But the Tokyo District Court acquitted him of all charges relating to Miss Blackman, 21, from Sevenoaks, Kent, who disappeared in July 2000 while working as a bar hostess in Tokyo.

Speaking after the hearing, her father Tim Blackman, from the Isle of Wight, blamed Obara's acquittal on failures by prosecution lawyers, and demanded an appeal in the case.

''I'm afraid to say the lack of justice for us today has been the failure of the prosecution team to develop the case adequately,'' Mr Blackman said.

''There is nothing that will change that Lucie is dead, but in many respects Lucie has been robbed of her justice.

''We believe our family deserves to get proper justice for Lucie, and that prosecutors should strongly consider an appeal.'' In court today, Mr Blackman and his 27-year-old daughter Sophie sat a few feet behind Obara and remained composed as the verdict was translated by a British Embassy interpreter.

Miss Blackman's mother, Jane Steare, could not cope with coming face to face with Obara and decided to stay at home in Kent.

Following the verdict, she said: ''I'm heartbroken, absolutely heartbroken. I just can't believe this verdict.

''My worst fears have come true.'' Mrs Steare added: ''As for my darling Lucie, I miss you so much.

''This aching void in my heart feels like it will never go away, but I truly believe that one day we will hug each other again.

''I love you so much and always will. Your mummy will never give up hope of finding justice and the truth.'' The dismembered body of the former British Airways flight attendant was discovered in a cave in February 2001, after a seven-month search, just 100 yards from Obara's apartment.

The prosecution alleged that Obara drugged and raped Miss Blackman before she died. It was then alleged that he chopped up her body into 10 pieces and encased her head in concrete at his luxury apartment.