LONDON - MARCH 29:  London Mayoral candidete, Boris Johnson, speaks to young people at a gang violence workshop on March 29, 2008 in London, England. The Peace Tree workshop was organised by Southwark Police and music company TwiceasNice at the Damilola Taylor Centre. Boris Johnson is on the campaign trail for position of Mayor of London. Getty Images logo Getty Images 50 months ago

LONDON - MARCH 29: London Mayoral candidete, Boris Johnson, speaks to young people at a gang violence workshop on March 29, 2008 in London, England. The Peace Tree workshop was organised by Southwark Police and music company TwiceasNice at the Damilola Taylor Centre. Boris Johnson is on the campaign trail for position of Mayor of London.