Mr Fisher told the jury that they picked out Mr Norton as he played cricket with James on a tennis court next to Erith Leisure Centre in Erith, Kent, on February 26 last year.

He said: “A group of between 10 and 15 youths gathered by the ­tennis courts and began shouting abuse at Ernest Norton and his son. These five defendants were part of that group. As the abuse worsened the group began throwing stones and pieces of wood at the father and son.

“Ernest Norton was struck at least twice on the head by these missiles – one of the stones hit him on his left temple causing a fracture to his cheekbone. He collapsed and suffered a heart attack.

“He received medical treatment at the scene, but was pronounced dead later that afternoon.

“This was an unnecessary, pointless and random attack by these five defendants. They were jointly responsible for the attack and ­jointly responsible for his death.”

The court was told that Mr Norton, of Erith, had had a triple heart bypass operation in 1977 and was suffering from ischaemic heart disease, but at the time of his death was not in any immediate danger. A post mortem revealed the stress triggered by the stoning was likely to have caused an abnormal rhythm in his heart beat and brought on
the attack.

Mr Fisher added: “Youth is no defence. They were quite old enough to know that the abuse of Ernest Norton and his son was wrong and that to throw stones and pieces of wood at them was deeply wrong.

“As much as they may regret his death, I am sure that Linda Norton and her family regret that man’s death even more.”

Mr Norton is survived by his wife Linda, son James and daughter Gemma.

Mr Norton’s widow Linda sat in the court just a few yards away from those accused of killing her ­husband.

The trial continues.