THE top cop who cut gun crime in New York says there's no secret to his success, just "basic policing".

Former police commissioner Howard Safir was asked to comment ahead of a summit at No10 today of police chiefs, community leaders, experts and Government ministers to try to find a solution to the gun crime crisis.

Mr Safir said his work was basic: he got intelligence about gangs and put trained officers on the street to work with the community.

Using athletes or recording artists as role models for kids was also part of his approach.

He added: "It is going after gangs and drugs and taking a zero tolerance approach to crime.

"Making sure that if criminals know they carry guns or sell drugs, if they even jump over a subway turnstile without paying their fares, they are going to get arrested."

Prime Minister Tony Blair was hosting the summit following the fatal shootings of three teenagers in the space of two weeks in south London.

Last night a leaked report revealed the scale of gang-related crime on the streets of the capital.

It revealed Scotland Yard knew of 169 gangs in London, each with an average of between 20 and 30 members.

More than a quarter have been involved in murder and nearly half in serious assault.

The report suggest there are more than 5,000 members in the gangs across the capital with gangs causing more than a fifth of all youth crime.

Hackney, in east London, has 22 gangs - the largest number in the capital.

Enfield, in north London, has 13; Lambeth and Merton in south London have 12 gangs each; Waltham Forest in north east London has 11 and there are also 11 Brent, north west London.

A spokesman for Scotland Yard said: "The document is a part of the Met's continued work to tackle gangs of all level of harm to communities."

One pressure group attending the meeting has criticised the decision by police to deploy more armed officers on the streets.

Mothers Against Murder and Aggression claimed it would encourage more criminals to carry a gun.

Spokeswoman Lyn Costello said: "We want guns off the street not more of them being used.

"The first time the police make a wrong call and kill a child they will be hauled over the coals."

Today's summit follows the shootings of Billy Cox, 15, in Clapham North, James Andre Smartt-Ford, 16, in Streatham and Michael Dosunmu, 15, in Peckham. Officers are also looking at two other murders in south London this month.

Billy was allegedly a member of the Clap Town Kids, a Clapham gang whose rivals include the PDC Crew in Brixton and the Blood Set in Peckham.

Mr Blair has said he wants to reduce the age at which a mandatory five-year sentence for carrying a gun can be imposed, from 21 to 17.

The minimum term for 18 to 21-year-olds was introduced under the 2003 Criminal Justice Act.

However, last March the Court of Appeal said the minimum could not apply to anyone under 21.

The Tories have claimed the Home Secretary could have resolved the situation with an order in Parliament.

Home Office spokesman in the Lords Lord Bassam said last May that such a measure was being considered.

Earlier this week Home Secretary John Reid said the implementation of a new law banning the manufacture of replica guns, due later this year, could be brought forward.

Hundreds of Christians were planning a "prayer walk" tonight through two boroughs blighted by the recent killings.