A Dutch court has convicted six amateur footballers and the father of one of the players of manslaughter after a volunteer linesman was kicked to death whilst officiating his son's junior club match.

Richard Nieuwenhuizen, a 41-year-old father of three, died from severe head injuries sustained while being ambushed and beaten by a group of teenage football players in an attack on 2 December that shocked the football mad nation.

Judges in Lelystad sentenced 50-year-old father, identified only as El-Hasan D, to six years in prison. Five teenaged players were given two-year sentences in youth detention for their roles in the attack and another was sentenced to a year.

Download the new Independent Premium app Sharing the full story, not just the headlines

A seventh player, age 15, was sentenced to 30 days in detention for assault. All the defendants insisted they are innocent. Their lawyers had argued that the linesman, Mr Nieuwenhuizen, had an underlying medical condition that contributed to his death but Dutch forensic experts said he died as a result of the beating. They have two weeks to appeal. Judges said the young players acted together in the fatal beating and gave them the highest sentences available.

"The seriousness of the event, the lack of a clear reason for it, the terrible consequences, the fact that they haven't accepted responsibility for their acts and the enormous shock it caused throughout society and the entire football world meant that the minors received the maximum possible sentence," the court said in a statement.

“We’re happy with the high sentences, because the worst thing for me is that they never admitted what they did,” Xandra, Mr Nieuwenhuizen’s widow, said. “This verdict gives us some kind of closure.”

The linesman was taken to hospital hours after being beaten by the players from the Amsterdam youth club Nieuw Sloten during an under-17 match in Almere. Initially Mr Nieuwenhuizen did not seek medical help although he was clearly badly shaken. He decided to go home and returned to watch another game game later in the afternoon.

"Suddenly he collapsed," Rob Mueller, a board member of the Buitenboys club, told Dutch television.

An ambulance was called and Mr Nieuwenhuizen was taken to hospital but he died a day later.

Mr Nieuwenhuizen's own son had been playing in the match. Four youths were arrested in the immediate aftermath of the killing, followed by another three teenagers and a 50-year-old man a few days later.

The linesman's death stunned and horrified the Netherlands.

You can’t imagine it happening,” said Ajax coach Frank de Boer. “That boys of 15, 16 years short circuit like that. You wonder about the parenting.”

More than 12,000 people attended a silent march for Mr Nieuwenhuizen in Almere on 9 December.

The KNVB (Dutch Football Association) cancelled all 33,000 amateur matches scheduled for the weekend after the incident. Clubs in the Netherlands top division, the Eredivisie, held a minute's silence.