A 21-year-old bank worker convicted of stabbing his parents to death has been jailed for life.
Roy and Joan Clarke were killed in the home they shared with their son
Michael Clarke, who was obsessed with knives, had denied killing Milroy, 70, and Joan, 56, and leaving them in a pool of blood to go to a rock concert.
But a jury at Bristol Crown Court found Clarke, described as a martial arts fanatic, guilty of the murders which took place in Melksham in 2004.
The judge told him he must serve at least 28 years.
The court had heard how he amassed a huge collection of lethal weapons.
The jury of seven women and five men took more than 16 hours to find him guilty last Thursday on two counts of murder by a majority of 11 to one.
Bristol Crown Court had earlier been told Mr Clarke Snr - a retired policeman - suffered 17 separate stab and slash wounds in the attack. Mrs Clarke had been stabbed 14 times.
After killing them, Clarke went to Wembley Arena with friends to watch a Blink 182 concert, returning to the house in the early hours of the next morning and pretending to discover the bodies.
Clarke had denied the killings, claiming he had a perfect relationship with both his parents.
A second defendant, Stuart Painter, who was charged with helping cover up the crime, has been found not guilty.
Mr Justice Pitchford told Clarke he had been shown "love, devotion and pride" by his unsuspecting parents.
He told Clarke: "You were able, having extinguished their lives with several expertly delivered blows with a knife, to walk out of the house and pretend to enjoy a day in London."
Clarke, who had built up a collection of more than 100 knives and weapons, stabbed his father in the head, neck, chest and back.