Five boys have been sentenced to two years' detention for killing a father who collapsed with a heart attack after being pelted with stones and rocks.
One of the stones fractured Ernest Norton's cheekbone
Ernest Norton, 67, was playing cricket with his son at a leisure centre in Erith, south-east London, when he was targeted in February 2006.
The pair came under a hail of missiles and two stones hit Mr Norton's head.
The boys, now aged between 12 and 14, were convicted of manslaughter and violent disorder in August.
Passing the sentence at the Old Bailey, Judge Warwick McKinnon said: "The conduct of all of you as a group was utterly disgraceful and criminally irresponsible."
A victim impact statement by the victim's wife Linda Norton, read out in court by prosecution counsel Anthony Orchard, said: "Ernie's death has affected our lives in so many ways. We are still trying to be normal and enjoy ourselves again but I don't think I ever will."
The statement said Mr Norton's death had a "dramatic effect" on his daughter and son.
'Vicious, unprovoked attack'
Following the sentence, Det Insp Clive Hayes said he hoped the "tough sentence" will "act as a deterrent" to other youths tempted to get involved in anti-social behaviour.
He added that Mr Norton's family was "satisfied" and felt "justice has been done".
The boys wept and hugged their parents following sentencing.
Judge McKinnon said: "This was a vicious, entirely unprovoked and sustained group attack involving a barrage of missiles."
He added the boys "hyped" themselves up by "earlier rowdy mischief and misbehaviour" before attacking Mr Norton.
A jury heard Mr Norton was hit on the head at least twice.
"A child would realise your actions were dangerous, running the risk that injury would result. I am satisfied that each one of you were aware of that danger," the judge said.
The father and son were playing cricket in the tennis court
Mr Norton had set up stumps with his 17-year-old son James in a tennis court to practise bowling.
But they were approached by up to 20 youths who began shouting abuse including "rubbish bowler" and "go back to the old people's home".
Mr Norton tried to scare them off but they threw stones, rocks and pieces of wood at him and he collapsed, bleeding heavily.
"We were just keeping ourselves to ourselves," James Norton had told the court.
"It just seemed they wanted to pick on someone."
James and his mother Linda watched as an off-duty police officer tried in vain to resuscitate Mr Norton.