A Waitrose lorry driver swerved across a busy London road to halt two moped riders who were being chased by police.
The pair were being pursued by police through Catford while riding on a scooter on August 1 at around 8.15pm.
At one point in the pursuit the rider sped up and drove directly at an officer knocking him to the ground, leaving him injured, police said.
He then made off along Brownhill Road where the Waitrose heavy goods vehicle swerved in an apparent effort to stop them in their tracks.
The scooter crashed into the lorry and the two riders fled the scene on foot, police said.
A Scotland Yard spokesman said both rider and pillion passenger ran from the scene in different directions.
The driver of the lorry was not arrested. Officers said the lorry and driver were inspected by the Met's Commercial Vehicle Unit and the driver was not reported for any offences.
A 15-year-old was arrested on suspicion of robbery, assault on police, and failing to stop at the scene of an accident. Inquiries are ongoing to trace a second suspect.
Kay Sloane, 36, told the Sun: “It was really frightening. I was putting the children to bed at around 8:15 when I heard this almighty bang. My husband thought it was thunder.
“The moped crashed into the police man on his bike first – how he’s not killed anyone or himself I don’t know.
“What would have happened if I was going out or coming in with the children?
Video footage of the aftermath was posted to Twitter.
The lorry can be seen in a diagonal position across the entire road. A moped can also be seen on the ground along with police cars and an ambulance.
Waitrose refused to comment.
Lewisham police are investigating. Witnesses are asked to call 0208 284 8365 or 101 quoting CAD 7403/01 August. To remain anonymous call Crimestoppers on 0800 555 111.
