The mum of a teenage boy shot dead in Streatham Ice Rink has made a heartfelt appeal for help to find her son's killers on the third anniversary of his death.

Tracey Ford described how her devastated family were still struggling to come to terms with the loss of her “fun-loving and innocent” son, James Andre Smartt-Ford. The 17-year-old, known to his friends as Andre, or Dre, was gunned down on February 3, 2007, while with his girlfriend at a disco event attended by more than 300 people.

She told the Streatham Guardian she was still haunted by the screams of his girlfriend when she rang to say he had been shot.

She described how her daughter Becky, now 17, slept with a quilt belonging to her brother for more than a year and has only recently gained the strength to speak about him.

She said: "The people out there who know who did this cannot allow the perpetrators to have killed people and nothing gets done.

“Imagine if this was your family, or your son. Think about how this would affect your own life, because you would be devastated like the rest of our family."

Her tragic appeal came as police offered a £20,000 reward for information.

Some 17 people have been arrested as part of the investigation - including six on the night of the shooting - but no-one has ever been charged in connection with the killing.

Police believe there are witnesses and people in communities who have key information about the murder, but have been either scared, or had an "allegiance" which meant they did not want to come forward.

Detective Chief Inspector Gordon Allison, from the Met's specialist shootings team, Trident, said: "It is three years on from this brutal murder. Perhaps young people who now have children of their own will have a different perspective on what happened that night, and will want to do something to bring some peace to Andre's family."

He said 16-year-olds often did not want to "break a code" and had a different priorities in their lives, but three years on this could change.

D Chief Insp Allison said "a handful" of witnesses had already come forward since the reward was offered.

Andre was gunned down at about 10.55pm in front of dozens of witnesses.

He was in the area at the bottom of the stairs leading on to the ice, when he was approached by a black youth wearing dark clothing. It is at this point that two shots were fired at him.

He managed to stagger a few metres on to the ice, before collapsing.

Andre was rushed to St George's Hospital in Tooting but died before midnight. A postmortem examination gave cause of death as gunshot wounds.

Last week officers leafletted key estates in their investigation, and visited the ice rink when another disco night was held.

D Chief Insp Allison said: "We want to hear from anyone who may remember something from that night and ask that those who may not have spoken to us before to come forward and help us bring the murderer to justice."

Anyone with information should call 020 8247 4554 or Crimestoppers anonymously on 0800 555 111.