There were 11 youth homicides in London from January to October 2009
The number of primary school pupils stopped and searched for knives in London has soared, police figures show.
Almost twice as many 10-year-olds were searched in the capital in the year up to March compared with the year before.
Figures revealed 755 10-year-olds were searched by officers in the 12 months to March 2009, compared with 420 during the previous 12 months.
A Metropolitan Police (Met) spokesman admitted that some ethnic communities were "disproportionally affected".
Although more white young people were searched than any other group, a disproportionate number of those searched were black.
The Met said the figures were a result of a huge crackdown on knife-carrying in the wake of a series of teenage murders and knife attacks.
The force's Operation Blunt has targeted young people suspected of carrying knives in the hope of cutting the number of victims of attacks.
The number of youths aged between 10 and 17 searched by police rose from 123,819 in 2007/8, to 185,489 in the 12 months to March 2009.
A Met spokesman said: "The use of stop and search is a powerful tool to combat youth violence and deter the carrying and use of weapons on our streets.
"This has been stepped up since Operation Blunt Two and we intend to continue this activity as we believe that it prevents the loss of young lives."
Police figures show the number of young people killed and seriously injured by knives has fallen dramatically this year.
There were 11 youth homicides in London between January and October 2009 compared with 28 for the same period in in 2008, according to Met figures.
But Southwark councillor Jenny Jones, a member of the Met Police Authority, said police must tread a fine line between enforcing the law and maintaining the support and confidence of young people.
"Just one bad interaction can colour a young person's view of police for life," she said.
"This can be self-defeating - the police may be better off putting more work into schools and multi-agency work."