The foster sister of a promising athlete who was gunned down in cold blood by gangsters on a council estate has told how she fears her two-year-old son could become a future victim of Lambeth’s gangland violence.

Natalie Williams, 38, said the killing of 17-year-old Herne Hill harrier runner Sylvester Akapalara, who was part of Richmond College’s gifted and talented athletic programme, in December 2010 in Peckham had “changed Christmas time forever” for her and her family.

She said: “The only thing we can do is console ourselves with the memories of Sylvester – his life was cut short too early. [His death] shook us up a lot.

“My mum in particular found it very difficult.”

The administration manager said her two-year-old son Blake, who she lives with in Knolly’s Road, Streatham, had become very close to the teenager before his death and still continues to ask her where he is.

She said: “[Sylvester] was like part of the family. He was very good with kids. “Now [Blake] goes into his bedroom and asks ‘Where’s Sylvester?’ but he knows he’s gone.”

Ms Williams, whose mother fostered Sylvester for almost a year before he was killed, has spoken out after 19-year-old David Nyamupfukudza was jailed for 26 years at the Old Bailey last month for the brutal murder.

Fellow GMG (Guns, Murder, Girls) gang member Sodiq Adeojo, 20, of Shurland Gardens, Peckham, was previously jailed for a minimum of 30 years for his part in the murder.

Last week, she fought back tears as she told the Streatham Guardian her concerns about the future feuds her son might have to face.

She said: “It makes me very sad.

“I think you will find the majority of black families are saddened. Individually we have to try our hardest with our children, and we have to come together because it is a small world.”

“When I was a teenager I do not remember things like this happening. We could go up and down the street.

“You proved your struggles with your fists, not with guns and knives. “This is just mindless violence to me.”

Last month, Steve Bosley, the secretary at the murdered athlete’s former club, said Mr Akapalara had “all the attributes” to make it as an Olympian.

Ms Williams said: “It was so ironic that he was an athlete – he could run like lightning. But they cornered him.

“That cuts you up – and you think ‘how does that happen?’ “You can only be overjoyed that these boys are going to pay with their freedom.”