Ernest Norton lived nearby with his wife and son

Ernest Norton, 67, suffered a heart attack and died after he and son James, 17, were targeted by the gang in Erith, south-east London, in February 2006.

James said his father lay unconscious and bleeding after objects rained down on them, the Old Bailey heard.

Five boys, now aged between 12 and 14, deny Ernest Norton's manslaughter.

James, now 19, was bowling a soft cricket ball at stumps set up in the tennis courts outside Erith Leisure Centre.

Bleeding head

They had been practising for about 20 minutes, with his father standing behind the stumps catching the ball, when they noticed 15 to 20 youths throwing stones at the centre.

"We just carried on trying to ignore them and they moved on walking further down towards us along the path, and that's when they started noticing us I suppose.

"Quite a large number made it over the fence. They were just laughing."

He told the court: "Obviously I was worried about what could happen. It seemed like we were trapped in."

The teenager described hearing a "thud" behind him after his father was struck.

"That's when I turned round to see my dad collapsed. You could see blood coming from his left temple," he said.

He added: "We were just keeping ourselves to ourselves. It just seemed they wanted to pick on someone."

The five defendants also deny violent disorder.

The youngest gang member was just 10 at the time.