A 13-year-old boy has been charged with the murder of Christopher John Barry.
The 53-year-old was killed in Edmonton on Sunday evening.
Mr Barry, known as Jack, was stabbed as he tried to enter his block of flats following an argument with a group of teenagers.
He was pronounced dead at 8.40pm. His killing was the third in 16 days in the Edmonton area.
The teenager has been remanded in custody and is set to appear at Highbury Corner Youth Court today.
Four other boys - three aged 14 and one aged 13 - arrested on suspicion of murder have been bailed to return to an east London police station in January pending further enquiries.
Alison Earle reported live from Brickland Court flats, where Mr Barry was killed.