Neighbours have spoken of the shock today of the death of a man stabbed on their doorstep in what appears to be a row involving two families last night on the Isle of Dogs in east London.

Police were called at 7.20pm to reports of a knife incident in Millwall’s new Lanterns Way housing complex half-a-mile from Canary Wharf.

They found a 20-year-old man bleeding on the ground who was pronounced dead at the scene.

A murder investigation was started by detectives from the Met’s Homicide & Serious Crime Command as Scotland Yard launched an appeal for witnesses.

Three others were injured in the incident and were treated by ambulance crews at the scene.

“I’m sad for the boy who died,” widowed mother-of-six Rehana Rahman, 42, told the Advertiser. “They’re a religious family. We all go to the mosque in West Ferry Road.”

She heard shouting two doors away from her ground-floor window and said she saw a man and woman arguing.

“It all went quite—then 20 minutes later there was screaming and people were fighting in the street,” she added.

“I was horrified when I saw the boy with blood on his face. I saw him fall to the ground. There was blood from his mouth.”

Police arriving in the street arrested a man and woman, who were taken to separate east London police stations last night for questioning.

Next of kin have been informed of the man’s death, but Scotland Yard isn’t releasing his name until formal identification at a post mortem likely to be held at Poplar mortuary later today.

Scotland Yard is appealing for witnesses or anyone who was in Larson Walk in Lanterns Way, a cul de sac off Millharbour, or anyone with information, to call police on 101 or Crimestoppers anonymously on 0800-555111.