Boy , 13 , admits stabbing a builder outside a block of flats in north London . Christopher John Barry pleaded guilty to murdering Teenager , who was 53 . The 13-year-old will face a minimum of 12 years in jail after sentencing . Mr Barry was said to have been involved in a row with a group of youths . Two boys followed him into the building before he was stabbed , police said .
Boy , 13 , admits stabbing a builder outside a block of flats in north London . Teenager pleaded guilty to murdering Christopher John Barry , who was 53 . The 13-year-old will face a minimum of 12 years in jail after sentencing . Mr Barry was said to have been involved in a row with a group of youths . Two boys followed him into the building before he was stabbed , police said .