Four teenagers who deny murdering a schoolboy in Edmonton two years ago are due to start their trial at the Old Bailey on Monday.
Billal Lariba, 18, of Mayall Close in Enfield Lock, Brandon Hamilton, 18, of Broad Oak Avenue in Freezywater, and Tershan Edwards, 19, of St Albans, are charged with murdering 15-year-old Negus Mclean in Westminster Road in April 2011.
A 16-year-old boy, who cannot be named due to his age, was also charged with murder and is due to appear before the court.
Negus Mclean, a former Edmonton County School pupil, was stabbed in the chest and thigh as he tried to protect his brother from being attacked.
Adam Langston, 18, of Beaconsfield Road in Enfield Lock, and a 16-year-old girl from Enfield were also charged in November with perverting the cause of justice.