A woman and a boy have been killed after a car police were pursuing crashed into a family.
Credit: ITV London exclusive
Both pedestrians were pronounced dead at the scene in Lennard Road, Penge.
Three girls also suffered multiple injuries and have been taken to hospital.
Witness Venissa Vassell, who helped in the aftermath, said she performed CPR on the injured lady but "it wasn't working".
She said the boy who died was aged around 10 and was fine one moment, but then "by the time I came back to speak to the little girl to say 'your brother is alright', he was passed out."
Ms Vassell said twin girls aged around seven were trapped under the car and "20 people" came to lift the car up to free them.
The girls "crawled out", she added, but another girl, aged around 11, was screaming 'I can't feel my legs'.
Three ambulance crews, two incident response officers, an advanced paramedic and London's Air Ambulance attended the scene in south east London at just after 2pm.
The car was being chased by police after being reported as stolen.
Officers started pursuing the car in Birkbeck Road, Beckenham, about five minutes before the accident.
Police have arrested the 23-year-old male driver on suspicion of causing death by dangerous driving and theft of a motor vehicle
Tayla Goodman told Sky News she saw "children running away" from the scene in "absolute tears, unable to speak" after the car "ploughed into the grass bank".
The Directorate of Professional Standards and Independent Police Complaints Commission have both been informed.