The Metropolitan Police said officers arrived at the scene after receiving reports that a child had fallen from height. Paramedics from the London Ambulance Service provided first aid before the girl was taken to hospital, where she died.
A Met Police spokesperson said: "Our thoughts and deepest sympathies are with the child's family and loved ones at this incredibly difficult time." They added that an investigation into the circumstances is ongoing, but the incident is not believed to be suspicious.
The police have asked anyone with information to contact them on 101, quoting CAD 2424/24OCT.