He was found just inside a loft puffing off smokes from a stick of cigarette after carying out his callous killing.
Daniel Dighton has been caged indefinitely for public protection after found guilty of the manslaughter of his retired teacher parents.
Daniel, 35, was told he would have to serve a minimum of 15 years and would only be released if it was thought he was no longer a danger after he amitted he killed both parents in a fix of insanity in their home in Croydon.
He had been cleared of cleared of murdering former headmaster Barry, 61, and Elizabeth, 60, but the Old Bailey jury found him guilty on 11-1 majorities of manslaughter on the grounds of diminished responsibility.
The court was told how Daniel attacked his parents with two knives at the family home in Campden Road, south Croydon, south London, in September last year. After he was nagged and called an idiot for laying about around the house.
He flew into a rage after his parents returned from a shopping trip to find him still in bed and hung-over stabbing his mother 28 times and then stabbed his father four times as he( the father) attempted to help after the stabbing.
Dighton was sentenced to two indefinite terms to run concurrently for his “savage” crimes.
A doctor told the court Dighton may have been suffering from an acute stress reaction. parents.
Judge Timothy Pontius told him: “This was a truly horrific act of savagery.”
“Yours was always a loving and close-knit family. Your parents were affectionate, generous and loving,” he said, adding he was never suppressed for his will but rather spoilt by the loving parents regrettably falling short of their expectations.
He had chosen an “indolent life” and was content to live at home and be supported by his parents.
“The full horror of your acts on that day and the devastating consequences to the rest of your family are likely to remain with you for the rest of your life.
“You were not an ill treated child, unloved and neglected for years, finally snapping and killing your hated abusers.
“Rather the evidence demonstrates very clearly yours was always a loving and close knit family. Your parents were affectionate generous and caring, to the extent that you were regarded by some, and indeed yourself, as a spoiled child.
“You have described them as magnificent parents and your childhood as fantastic. I accept you loved them as much as they loved you, hence the heavy burden of responsibility you bear for causing their deaths in such an appalling act of truly horrific savagery.
“You undoubtedly lacked their motivation and full self confidence and this, no doubt, fell short of their expectations.
“I must, and do, have careful regard for the fact that your responsibility for your actions was substantially diminished.
“Prison is the only realistic course open to me. Your future behaviour remains wholly unpredictable.
Cops followed blood drips upstairs to find Daniel Dighton hiding in the loft smoking a cigarette, with blood stains on his jeans.