The number of teenagers killed violently in the UK has fallen by 30% in one year, BBC research has found.
The BBC teen homicide database, which records murder and manslaughter cases, shows 51 10 to 19-year olds lost their lives in 2009 compared with 72 in 2008.
Most 2009 victims were male and half of all those killed were stabbed. Twelve were beaten and two were shot.
Police say anti-knife crime tactics explain the drop, but critics argue it is too early to make such conclusions.
The BBC News website's database shows that of the 51 young people killed so far this year, the youngest was just 10 years old and the oldest 19. The most common ages of victims were 17 and 18.
Most of the victims were white and male - just nine of the 51 were girls.
While England saw the vast majority of cases, Scotland had eight, Wales three and Northern Ireland two.
Of all cities, London had most deaths - with 13 of its teenage residents losing their lives to violence. However, this is a significant drop from 26 in 2007 and 30 in 2008.
The news comes just days after another teenager was stabbed to death in the capital. Art student Salum Kombo, 18, was found dead with stab wounds in east London on Sunday.
The only other cities to see more than one teenage homicide this year were Nottingham (three), Glasgow (two), Manchester (two) and Liverpool (two).
British Crime Survey (BCS) figures for England and Wales released earlier this year appear to support the BBC's findings.
They also showed a fall in the overall number of homicides involving a knife or other sharp instrument from 270 to 252 between 2007/08 and 2008/09.
However, the survey recorded a rise in the number of attempted murders involving a knife - up from 245 to 271.
Historically, the BCS also shows the proportion of violent crimes in which a weapon is used has remained stable over the last decade at about 21%.
A Home Office spokeswomen said the drop in teenage deaths this year was "testament to the good work of police and community engagement teams across the country".
Knife crime tsar Deputy Chief Constable Alf Hitchcock believes the Tackling Knives Action Programme, launched in June 2008, is part of the reason for the fall.
The multi-million-pound venture, which involves five government departments and 16 police forces, focuses on high-visibility policing, education, after-school activities and support for parents.
DCC Hitchcock said youth violence was better understood and the authorities were more adept at spotting the early warning signs in young people.
"There is a clear understanding that these factors interact and how we deal with this is to work together."
He added: "The key is maintaining joined-up policy."
But Richard Garside, of the Centre for Crime and Justice Studies at King's College London, believes it is too early to say whether youth violence is decreasing.
The families of victims Jimmy Mizen and Rob Knox campaign against crime
He also questioned whether police-led measures, such as the Tackling Knives Action Programme, could ever have any lasting effect.
He said: "Our research found the most significant impact was from nurses in A&E talking to people coming in with wounds - questioning what they were doing with their lives and talking to them about their lives."
He added: "I think the evidence for the impact of the Tackling Knives Action Programme is not strong."