The mother of a teenage boy stabbed to death outside his West Norwood school has made a tearful plea for information to bring her son's killers to justice.

Zac Olumegbon, 15, was attacked as he arrived at Park Campus School on Friday morning by four men who pulled up in a green Nissan car.

Police said the attack was pre-planned.

The boy's mum Shakira Olumegbon, 52, said: "I know a mother, a father, a brother or sister knows who has done this.

"It's not revenge I'm after. But I want that mother to help bring our community together because this is too much.

"It's happening a lot. We have to stop this."

She wept as she clutched a photograph of her smiling son in his school uniform, and spoke of his dreams to become an actor.

She said he had performed at a conference the day before he was murdered and that night, before he went to sleep told her: "'Mum. Mum, I know what I want to do.'"

She added: "He said, 'I want to go to America for a year and I want to come back to a sixth form college, and because of my performance they promised me a job as an actor.' He was full of hope."

Zac's sisiter Tayo, 28, made a direct appeal for her brother's killers and anyone that may be able to help police to come forward.

She said: "I know people are scared, but we really need this information. We don't want it to happen again to another family.

"You see these things all the time and you never think it's going to happen to you."

Zac's brother Debo, said: "I feel like I've lost a part of me, in a way. His life was just taken away. For what? We don't know.

"There's no reason whatsoever. I'm just hoping that people can look at my mother, and just imagine that it was your mother, your family."

Mrs Olumegbon added: "He's not a violent boy. He's got a big mouth but he's not a violent boy at all. He's a small boy."

She spoke of his fear as he walked to school. She said: "Every time he went to school, he said, 'Mum, I'll go the other way, don't worry. It might take longer to get to school, but I'll walk the other way.'"

Tayo said: "He was afraid of certain individuals in the Brixton area, so he didn't want to be around."

She said arguments could start very quickly on the streets: "I don't really think it takes that much these days anyway. Just a little argument, or someone looks at someone the wrong way."

Anyone with information is asked to contact the incident room on 020 8721 4205 or Crimestoppers anonymously on 0800 555 111.