A 35-year-old who butchered his elderly parents in their own home after his mother threw a book at him had his sentence slashed by top judges this week.

  Daniel Dighton, described by one psychiatrist as a fantasist with schizoid traits, killed Barry and Elizabeth Dighton with two kitchen knives as he and his parents prepared to leave on their annual holiday to France.

  Dighton had previously given up his job as a teaching assistant to take up a teaching post in Thailand which fell through, London’s Appeal Court heard.

  He fooled his friends in the local pub into believing he had taken up the foreign job, even applying fake tan to convince them he had been in the Far East.

  In truth he had never left the UK, Mr Justice Langstaff told London's Criminal Appeal Court.

  On the day of the killings Dighton had woken late with a crushing hangover, the court heard, which set the scene for a blazing row with his parents.  He later told a psychiatrist that he snapped after his mother hurled a book at him and spoke to him in “derogatory” terms.

  He attacked Mrs Dighton, 60, with the knives she had packed for their holiday, stabbing her 28 times in what Mr Justice Langstaff termed a “savage” attack.

  Mr Dighton, 61, the former Head of Elmhurst School for Boys, in South Park Hill Road, was then despatched with four stab wounds.

  When police arrived they found Dighton smoking upstairs in his attic room. He told them he was up there because his mother would not let him smoke elsewhere in the house.

  The attack occurred at the family home in Campden Road, South Croydon.

  Dighton was put behind bars indefinitely for public protection (IPP) - a sentence which is almost identical to a life term - at the Old Bailey last October after he was convicted of manslaughter on grounds of diminished responsibility.

  His case reached the Appeal Court as Dighton’s lawyers challenged the 15-year minimum term he was ordered to serve before he can even apply for parole.

  Mr Justice Langstaff, sitting with Lord Justice Pill and Mrs Justice Macur, said Dighton had expressed “real remorse” and was guilty of an act of sudden rage against two people he had loved.

  “We have come to the conclusion that the minimum term for these distressing and horrible offences was simply too high,” concluded the judge, cutting the term from 15 to 12 years.