A suspected stolen car being chased by police has ploughed into a family leaving a woman and child dead.

Witnesses described the horror of the aftermath of the smash on Wednesday in south-east London, which saw the car crash into a group of pedestrians.

Venissa Vassell, 18, heard sirens and a car screeching as she walked from a nearby train station and immediately ran to help.

She said there were twin girls aged around seven trapped under the car and about 20 people came to lift the car up to free them.

The girls "crawled out", but another girl, aged around 11, who was later taken away by ambulance, was screaming "I can't feel my legs".

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A woman, believed to be in her late 30s or early 40s, and a 10-year-old boy she was related to, were killed, Ms Vassell said.

She said: "I did CPR on this lady. I blew in her mouth. It wasn't working."

Ms Vassell said that the boy who died 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.

"You can't physically do nothing to a body that's in that condition, you can see bones and flesh - I think he shed more blood than anyone else there."

She said that the accident "all happened too quick" and she "could not explain" what she saw.

A man who lives near the crash site said that a black car was being chased by two police BMWs when it tried to turn into Lennard Road, Penge.

"He lost control and ploughed into a family that was walking on the pavement down Lennard Road.

"People were trying to lift a car off a little girl. The police officers that were chasing were distraught," the man said.

"It was a horrific scene on a sunny afternoon in a sleepy place."

Another eyewitness, who also did not want to be named, said that apart from the two people who died, the casualties who were children were being taken away by ambulance.

Scotland Yard said: "At approximately 2.05pm on Wednesday August 31 a car was in collision with a number of members of the public in Lennard Road.

"The car was being pursued by police at the time of the collision. London Ambulance Service and London's Air Ambulance attended - two people have been pronounced dead at the scene.

"The driver of the car has been arrested and remains in custody at a south London police station."

Watchdog the Independent Police Complaints Commission has been informed and is sending investigators to the crash scene.

Scotland Yard's internal standards department has also been told.

In Lennard Road on Wednesday afternoon, a body wrapped in a red blanket could be seen before police erected blue tents.

The black Ford involved in the crash was on a grass verge as a helicopter flew overhead.

The road remained closed and several police officers were present.

A spokeswoman for London Ambulance Service said: "We sent multiple resources to the scene including three ambulance crews, two incident response officers, an advanced paramedic and London's Air Ambulance.

"Sadly, a woman and a boy died at the scene.

"We treated a further three patients, all girls, at the scene for multiple injuries and they were all taken to hospital."

There were 498 crashes involving a pursuit by Metropolitan Police officers in London in 2015/16, up from 434 in the previous year. There were 474 such collisions in 2013/14.

In England and Wales there were 21 fatalities in 20 police-related road traffic incidents in 2015/16, up from 14 the previous year. However the IPCC said it was the fourth lowest figure since 2004/5.