Inner-city teenagers are swapping ideas with police as part of a fresh bid to beat the capital's knife crime problems.
More than 90 schoolchildren are taking part in the new scheme aimed to shape the way youth violence is tackled.
Barry Mizen, whose 16-year-old son Jimmy was murdered in 2008, is among a panel of experts speaking to 14 and 15-year-olds at City Hall.
Emily Thomas, a prison governor at Cookham Wood, Duncan Bew, a trauma surgeon from King's College Hospital, and Commander David Zinzan will speak to the teenagers, all based in the south-east London district.
Scotland Yard hope the project will create a "large group of influencers" who will go back to their schools and peer groups to promote ways to reduce harm.
Police also hope to improve engagement between teenagers, the police and other leading agencies working towards the mutual aim of making London safer for young people.
Mr Zinzan said the event proved officers were "prepared to listen and try something different".
"Police have an important role to play but we need to harness the views of young people in dealing with this menace," he said. "The young people here have been especially chosen by their schools for their ability to communicate and influence. Police alone cannot solve this and today gives us a great opportunity to both give and receive messages."
Mr Mizen added: "It is important to recognise that young people are just as concerned about this issue as the adult population. It is after all young people who are affected by it the most.
"The forum at City Hall is an opportunity for adults involved in tackling violence to hear the views and experiences of young people, especially those identified as leaders in their own peer groups. When young people are included in the process their sense of ownership and self-worth is boosted, enabling them to recognise that their involvement in the solution is paramount."