One of the darkest hours in amateur football came on December 2, 2012 in the Netherlands: Richard Nieuwenhuizen was running the lines in a youth match between SC Buitenboys and SV Nieuw Sloten in Almere, just outside of Amsterdam. A controversial offside decision so angered some of the Nieuw Sloten players that after the final whistle six of them aged between 15 and 16 — along with one of their fathers — physically attacked Nieuwenhuizen, knocking him to the ground and kicking him in the head. The next day, the 41-year-old amateur football official died in hospital of a brain hemorrhage. Each of the players and the father involved in the attack on Nieuwenhuizen were later convicted of manslaughter and sent to prison.

Read more: German football referees strike over player violence

'Every incident is one too many'

Since Niewenhuizen's death, the number of reported incidents of violence at amateur matches has fallen steadily, from 485 in the 2011-2012 season to 257 in 2016-17, according to the Royal Dutch Football Association (KNVB).

"Every incident is one too many," the KNVB told DW in a statement. "There are 750,000 matches a year and unfortunately there are occasionally matches where unsporting behavior takes place or violence is used. If that happens, on or around the football field, this is worrying and we take action against it."

What the KNVB was referring to is a set of violence-prevention initiatives launched after Nieuwenhuizen's death, which mainly target youth players. The KNVB cooperates closely with the Dutch organization "Halt," which works to combat juvenile delinquency. Youth football players who are handed bans over violent attacks are offered behavioral training. The incentive for them to take this training is the fact that if they successfully complete the program, they stand to have their suspensions reduced.

Families of referees are also threatened

An emergency number has also been set up in the Netherlands that  the approximately 24,000 referees can call any time, day or night, to report any incidents of violence that they may have experienced. In cooperation with the KNVB, the organization "24/7" has been supporting traumatized football referees for years. Overall, the level of aggression is increasing, a 24/7 spokesperson told DW. In some cases it's not just the officials but also their families who are threatened, and they too can wind up needing psychological care.

As in Germany, where the number of referees has fallen steadily over the past few years (from 78,468 in 2010 to 56,680 in mid-2019), the Netherlands has also recorded a decline.

"But it is too harsh to ascribe that to an increasing threat [against officials]," the KNVB stated.

Far worse in England

Compared the Netherlands, the situation in England is far more serious, according to a study published by the University of Portsmouth in 2018. As part of the study, referees were asked if they were either verbally or physically assaulted in at least every other game they officiated. While in the Netherlands, 2.2% answered yes to the question, and in France it was 14.4%, in England 60% answered yes to this question.

Amateur referee strikes, such as those seen recently in Berlin and Cologne, have also taken place in England. One weekend at the beginning of March 2017 saw more than 2,000 amateur referees across the country refuse to officiate matches. They did so to protest against rising levels of violence towards referees. In January 2019, English referees threatened fresh protests to raise awareness of what was still a concerning trend. They disagree with an English FA study that claims just 0.01% of the 850,00 games in England per season involve attacks against match officials.

FA makes lowering violence a priority

At the beginning of the current football season, the reporting process for amateur referees was altered, according to the FA. All cases involving physical attacks now go to a national committee. The aim is to ensure regional committees are imposing the appropriate penalties. The English FA points to its "Respect" campaign, which has been running for around 10 years with the aim of convincing players and spectators alike to treat the country's 31,735 referees, from the Premier League down to the lowest English leagues, with respect.

A new campaign in the under-18 age category is still in its infancy. Young amateur referees wear purple jerseys which make players, coaches and parents aware that they are often of a similar age to the junior players. The response to the campaign so far has been positive, the FA says.

At the beginning of 2019, Ref Support UK, an organization that offers help and advice to referees, released worrying new findings. Over the past five years, the situation had grown worse.

"My fear is that it's going to take something very serious, or a death, before anyone will take it seriously," said Ref Support UK Chair Janie Frampton.

The organization wants to see referees wearing body cams, such as those already worn by police officers in the UK.