In London, it is the season of brutal stabbings. More than 50 people have been stabbed to death in the capital this year alone; four knife killings occurred in just a single day earlier this month. Hardest hit by the crime wave are young people from black immigrant communities and from economically depressed urban areas.  The Metropolitan Police, London's police force, has told its officers that their top priority has shifted from fighting terrorism to fighting knife attacks. Mandy Clark reports from London.

Knife murders are on the rise. They've  more than doubled in the last four years.

In 2004, 16-year-old Robert Levy was stabbed to death trying to protect his 11-year-old neighbor. His brother, Nathaniel Levy, says his world fell apart when Robert died. 

"On the day that he died I cried my soul away,"  Nathaniel said.

Robert Levy was one of 200 young people killed in violent knife attacks in the past several years.  

Hardest hit have been young men -- often from black immigrant families -- from Nigeria, the West Indies and other former colonies. Many are asking why this is happening.

Diane Butts, with London's police authority, says gang culture is a factor. 

"Some young people are using knives as a status symbol and that is born out of maybe their exposure to negative youth culture be it in terms of gangs, be it in relation to music and this sense of living fast and dying young has captivated some of our young people," she said.

But not everyone agrees.

Damilola Taylor, born in Nigeria, was only 10 years old when he was stabbed to death.  He was attacked, eight years ago, as he walked home from the library.  His father Richard says children are carrying knives out of fear -- fear of becoming victims. 

"They have the fear that out there it's dangerous and they feel if they carry a knife they feel protected, whereas it is the opposite," he said. "They think they are protected by carrying a knife, but it can be dangerous to them as well."

And the violence has spread beyond immigrant communities.

Recently, two French students were brutally stabbed to death in their London apartment.  It was apparently an attempted robbery. One of the students was stabbed 200 times. 

The recent stabbing of 16 year-old Ben Kinsella caused an outpouring of anger and sympathy.  Kinsella was stabbed trying to walk away from a fight at a pub.

Afterwards, a top judge in Britain described the recent murders as an epidemic.

Now, the government is getting tough. 

"If you carry a knife, our objective and determination is that you will be caught, you will be prosecuted, you will be punished," said Prime Minister Gordon Brown.

But Nathaniel Levy, Robert Levy's brother, says it's not just up to the government. 

"It is not just a job for them or for individuals," he said. "It's for society as a whole within this country to push forward to stem this problem."

The government points to an overall drop in crime in Britain, but acknowledges more must be done to get at the root causes and stop the knife crime wave.