Police are to hold US-style ceasefire summits with London's most dangerous gang members in a new attempt to tackle gun and knife violence.

The scheme is aimed at urging thugs to reform or face a major crackdown.

Details emerged a day after two killers were jailed for life for the machinegun murder of Oxford University hopeful Agnes Sina-Inakoju, 16.

Gunman Leon Dunkley, 22, and look-out Mohammed Smoured, 21, were told they must serve at least 32 years for killing the schoolgirl in a Hoxton takeaway.

Police seized a terrifying arsenal of guns the gang had hidden under the bed of a nine-year-old boy. The haul included two sub-machineguns capable of firing 800 rounds a minute.

The Met today revealed it took 16 sub-machineguns from London gangs last year. A total of 530 guns were seized, including 299 handguns, 181 shotguns, 24 rifles and a machinegun.

Most of the sub-machineguns seized were Uzi-style machine pistols favoured by military special forces and similar to the weapon used to murder Agnes.

Sources from Operation Trident, which tackles the gun violence, said the guns are suspected of being smuggled into the UK from eastern Europe. The ceasefire project has been launched as a trial scheme in Waltham Forest but is expected to be rolled out across boroughs worst hit by gang violence. So far nine criminals and their families are being offered help with housing, addiction, education and jobs in a bid to tackle the causes of gang problems.

The Gang Prevention Programme, run by Waltham Forest council and the Met, hopes to recruit 30 members to the three-year scheme. Gangsters are first invited to take part in the project and then hold a series of meetings with officials about their lifestyle.

A council spokesman said: "We're trying to tackle people who are the most involved in gang culture and those most at risk."

If support is refused, police advise people they will be targeted relentlessly. The spokesman added: "There is a zero tolerance approach to those who persist in their gang activities and do not engage with us."

Some estimates suggest there are 200 or more gangs in London, with a combined membership of 15,000. In some boroughs gang violence has become so serious that vulnerable youngsters are ferried to school in taxis to avoid disputed gang territories.