A 20-year-old man accused of murdering his drinking pal says his uncle urged him to kick the victim until he learned his lesson.

Paul Douglas alleges that his uncle Alan beat Steven Benjamin repeatedly on the head with a stick.

Douglas told the jury at Leeds Crown Court that he saw Mr Benjamin, known as Benji, on his knees while his uncle rained blows on him.

Douglas, who denies murdering Mr Benjamin, said his uncle told him: "Paul, kick him and make sure he's learnt his lesson."

Mr Benjamin, 42, of Lapage Terrace, Barkerend, was left to die in a pool of blood.

His body was found outside Alan Douglas' flat in St Hilda's Terrace, Thornbury.

Yesterday, Douglas' defence counsel Martin Bethel QC said there was no doubt that the defendant killed Mr Benjamin by kicking and stamping on his head.

Mr Bethel told the jury that Douglas, of Dick Lane, Thornbury, was using the defence of diminished responsibility. He claimed that the killing was manslaughter and not murder because Douglas suffered from an abnormality of the mind.

Mr Bethel said that the defendant was in the bottom one per cent of the population as far as intelligence was concerned. He had impaired social function that manifested itself from an early age in a conduct disorder. He was violent and abnormally aggressive as well as of very low intelligence.

Douglas told the jury on the day of the killing, October 18 last year, he smoked cannabis and began drinking at his uncle's flat at 9am.

He said his uncle later found money had gone from his bedroom and those present suspected Benji of taking it.

Douglas said that he and Benji began shoving one another.

His uncle told them to take the fight into the garden and they resumed the shoving outside.

Douglas said he fell over by the gate and his uncle shoved Benji and hit him repeatedly with a stick.

Douglas said he saw Benji unconscious on the floor. The next thing he remembered was coming out of a trance-like state. He said he was either still kicking Benji or resting his foot on his head.

Forensic biologist Samantha Warnakulasuriyah said it was a sustained assault involving a number of forceful blows being dealt to him after he had started to bleed.

"Paul Douglas has kicked Steven Benjamin using his heel and while he was injured and bleeding. He stamped on Mr Benjamin with considerable force," she told the court.

The trial continues.