Five London boroughs plagued by high gun crime are to be targeted in a new Met Police advertising campaign.

The campaign, which encourages people to shop gun-toting criminals, will target the boroughs of Brent, Hackney, Haringey, Lambeth and Southwark where gun crime is particularly prevalent It is being run by Operation Trident - a unit specialising in tackling gun crime in London's black and ethnic communities.

Lee Jasper, advisor to London's mayor on policing, said: "This advertising campaign, produced in partnership with the Independent Advisory Group representing London's black communities, emphasises the impact of gun violence for normal everyday people.

"It gives a message that people can do something positive by providing information to Operation Trident and that communities who support each other in this way can, and will, change things for the better."

Commander Cressida Dick, new head of Trident, said: "Every time there is a shooting at least one family is affected. This means that many peoples' lives, especially those of the victim's family, are changed forever.

"Over time these negative effects can be catastrophic, both individually for the people involved, but also collectively for the long-term strength of communities."

The new campaign features a radio adverts, street posters, posters in hairdressers, and partnerships with a range of music titles.

Operation Trident investigated 21 murders in 2001 and 24 last year. So far this year it has investigated 11 murders.