the existing zone in central london has cut pollution, but despite the health benefits many say they simply can t afford to replace and upgrade their vehicles. it literally is our lifeline. it s our only car that we ve managed to find in years now that fits all three car seats in as it needs to. i ve got twins with autism and another youngster as well. i haven t got the money to pay every time i go to the hospital. i live in chingford, so i m right on the edge of it. it s a radical change, but one that many cities across the world will be looking at closely. leigh milner, bbc news. a teenager who s alleged to have shot and killed 15 year old keon lincoln in birmingham earlier this year, has denied ever holding a gun. the 14 year old also told birmingham crown court that he d never carried a knife. keon lincoln was shot and stabbed outside his home in handsworth on 21st january.