narrator: gwenton sloley knows what he's talking about. he's an advisor to the police and also does community outreach work with young people with violent tendencies. they're often gang members, not even 16 years old. he is a former gang member os x time in jail himself. that was 10 years ago. times have changed. >> i think the young people have totally lost their way, and they haven't got positive role models to show them that what they're doing is wrong. they've lost their cultural identity. they don't respect anyone. because if you look, they're attacking normal citizens. in the street, on the buses. back in my day, you wouldn't be attacking someone's mum on the bus. reporter: knife attacks have become an epidemic in britain, where there were 34,000 of them last year alone. mainly in city outskirts like croydon, where poverty and unemployment are rife. real life here means drugs and violence. gwenton is taking us to meet one of croydon's main gang leaders. he calls himself "young chapel." we're meeting in a remote corner of a park in a

gwenton sloley who now trains police officers at the met and other forces on how to use their stop and kensal green. his murderer was sentenced last week for a minimum of 14 years. paul says if stop and search can stop the killings then it has his full support. we are going to talk to a viewer who got in touch. he is in high wycombe. thank you for talking to us. i want to ask all of you this one simple question. have you been stopped and searched? yes. how many times? recently, not as much as historically. over your lifetime? about 20 times. janet, have you been stopped and searched? yes. i have it has been in my car, but it amounts to the same thing. were you a police officer at the time? yes, i was. wow. paul have you been stopped and searched uncountable times. not recently. not in the last seven yea rs recently. not in the last seven years since i moved out of croydon, when i grew up in cou dorntion cou ntless when i grew up in cou dorntion countless times. you will know that the commissioner of the met says there is a link between stop and search and reducing knife crime. do you l