LONDON—Daniel Frederick, a 34-year-old father of three, was returning to his home on a London public-housing estate shortly after New Year’s when a group of teenagers stabbed him in the back seven times, yards from his flat near a children’s playground.
Mr. Frederick, a security guard, was targeted in a case of mistaken identity, police believe, but the assault was part of a crime trend that London’s mayor said this week would take a generation to solve: a surge in knife attacks in a country with relatively low levels of violent crime.
Mayor Sadiq Khan was speaking on Monday after a spate of four unrelated knife homicides in London in five days—the youngest victims were 15 and 17—put renewed focus on the national trend. A fifth knife killing followed that night.
With strict British laws making guns hard to obtain, knives have become the weapon of choice for members of London gangs, who youth workers say fight over territory and are prepared to kill over trivial slights. As stabbings become more frequent, more young people feel compelled to carry knives for their own protection, fueling a cycle of violence.
Mr. Frederick’s sister, Louise Samuel, was at the hospital with her brother when he died in January. The five assailants, all 16 to 18 years old, were sentenced last month to a total of 64 years in prison.
Ms. Samuel, a former youth worker, said she can understand the peer pressure that drove them. She has already forgiven the boys, she said, and would like to meet them, “Just to know why they are so angry.”
Mr. Khan has set up a special unit of police, youth workers and doctors to target the causes of violence, which he said were “extremely complex, involving deep-seated societal problems like poverty, social alienation, mental ill-health and a lack of opportunity.”
The British government last month established a £200 million ($261 million) fund intended to put children who are 10 to 14 years old and at risk of violence on the right track before they become perpetrators.
There is little consensus on why knife violence began increasing in 2014, after declining for years, and continues to grow. Some opposition lawmakers have blamed government cuts to police numbers, while those in power argue that changes in drug trafficking, such as the greater involvement of teenagers in the sale of drugs, is the key factor.
Youth workers say the closure of youth centers because of government budget cuts have left children to make their own rules on the streets. Numerous British charities are working to educate children about the dangers of carrying knives.
Despite prison sentences getting longer, the number of knife crimes in England and Wales jumped by 63% in the past four years, according to police statistics. Cities are the most affected areas with London hardest hit.
Murders in the capital rose to 153 between April 2017 and March 2018, compared with roughly 100 for each of the previous six years, according to London’s Metropolitan Police, which doesn’t specify killing methods. Across the country, knives are by far the most common instrument used in murders, official statistics show.
The knives themselves have gotten bigger, said Detective Inspector Paul Considine, who led the investigation into Daniel Frederick’s murder.
“The weapons we are coming across at the moment are zombie knives, specifically designed to cause major injury to human beings,” he said, describing a type of knife, banned in Britain, the size of a machete with serrated edges and jagged protrusions.
Knife crimes increase just after schools close, said Duncan Bew, a trauma surgeon who founded a charity that educates children about the dangers of gangs and carrying knives. “They feel that their environment is so violent that they aren’t protected unless they carry a weapon,” he said.
Dr. Bew said the injuries he has seen have grown worse in the past two years, with victims receiving multiple stab wounds in hard-to-treat areas, suggesting, he said, an intent to kill.
Yvonne Lawson tours London schools to tell the story of losing her son eight years ago to convince children not to carry knives. “It doesn’t get any easier,” she said in the two-desk office of the Godwin Lawson Foundation, in Tottenham, North London. “Sometimes I share that story, sometimes I break down and sob, sometimes I never get to the end.”
Godwin Lawson, a 17-year-old promising soccer player and former altar boy, was killed by a single stab wound to the heart in 2010 when he tried to break up a fight involving a friend.
“As a Christian, we brought him up to be caring and to look after others,” Mrs. Lawson said.
The young man that killed her son, now in prison, has requested to meet her, as has his family. She will, she said, as she leafed through photos of Godwin spread across her desk, but not yet.
“Forgiveness is part of healing and when I am ready I would like to…but it has got to be when I am ready.”