The man found guilty of murdering binman Stephen Whitehead claimed his responsibility was diminished by his moderate learning difficulties - giving him the capacity of an eight-year-old.
Aaron Jenkins (20) was convicted today following a week-long trial at Preston Crown Court and will be sentenced on March 3rd.
Jenkins admitted bludgeoning Stephen Whitehead to death with a sledgehammer at Pendle Skips when he broke in on July 25th.
But he claimed he did not premeditate the attack and admitted manslaughter on the grounds of diminished responsibility.
Three weeks before the killing, the pair had come to blows when Mr Whitehead had called Jenkins lazy as they worked together in the yard.
After a fist fight which left both men requiring hospital treatment, Jenkins was told not to come back to his casual job at the sorting and recycling plant in Burnley.
On July 25th, Jenkins had been drinking with two teenagers. Mr Whitehead had also been drinking in a number of local pubs and had decided to sleep at the yard - something colleagues said he sometimes did.
The boy Jenkins was with said he was considering buying a motorbike and Jenkins said he knew where there was one he could steal.
As the trio made their way to the skip plant where Jenkins had previously worked, the boy decided he was not going along and Jenkins and the girl - who can not be named for legal reasons - carried on.
At the gates, Jenkins told the girl to wait while he climbed over and made his way to the canteen area, where a motorbike was stored on an upstairs mezzanine.
But as he approached the canteen he heard a radio playing and saw Mr Whitehead asleep between two chairs and thought: “Payback time.”
Jenkins then took the motorbike to the bottom of the canteen steps but realised it would be too heavy to carry over the gates.
He walked to an office where the sledgehammer was kept and returned to where Mr Whitehead was sleeping, raining down five or six heavy blows to his head.
He then returned to the teenager who was waiting for him by the gates.
She told the court: “He just climbed over the gates and we just walked and he was like, normal at first.
“As soon as we got onto the main road, that’s when he started looking around and being weird and then Aaron told me he thinks he’s killed someone.
When colleagues arrived at the plant to start work on July 27th, Mr Whitehead was found slumped in the chair with severe head injuries.
Jenkins was hanging around the gates when the site opened, claiming to have come to speak to the boss about getting his job back.
But during police interview, Jenkins admitted he killed Mr Whitehead. He claimed diminished responsibility due to having moderate learning difficulties.
Consultant forensic psychiatrist Dr Lucy Bacon told the court he had difficulty in controlling his impulses but prosecutor Francis McEntee argued there had been no altercation between the men when they had been together at the hospital, following the fight.
The teenage girl who waited at the gates also gave evidence, telling the court she had provided a false alibi for Jenkins as she was afraid of what he would do if she did not do what he told her.
But the jury found her guilty of attempting to pervert the course of justice. She will also be sentenced on March 3rd.