Five boys aged from 12 to 14 burst into tears as they were found guilty of killing a father they spat at, insulted and pelted with sticks and stones.

Ernest Norton was playing cricket with his 17-year-old son, James, on a Sunday afternoon in February last year when they came under a hail of missiles.

Two stones, one the size of half a brick, struck him on the temple and fractured his cheekbone. He suffered a heart attack and collapsed to the ground. As the 67-year-old lay dying, his wife, Linda, rushed to his side.

Mr Norton, for 30 years a house husband who looked after his two children, James and Gemma, 26, died at the scene.

The five boys who killed him, the youngest of whom was just 10 at the time, were convicted at the Old Bailey yesterday of manslaughter and violent disorder.

Mr Norton had gone with James and Linda to their local leisure centre in Erith, south-east London and, while his wife went to the gym, he and his son set up stumps outside. But they were soon surrounded by up to 20 youths, who began to shout insults. Mr Norton tried to scare the boys 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 told the trial. "It just seemed they wanted to pick on someone."

An off-duty police constable, Christopher Malone, tried to save Mr Norton's life, but it was too late.

Just days before the end of the trial Gemma gave birth to Ceinwen, a baby girl. "Now he has missed his first grandchild," Mrs Norton said. "He would have been thrilled to have a grandchild."

The five boys will be sentenced on 19 October.