Video from the streets of London has captured the moment a Metropolitan police officer was knocked off his bike in a seemingly unprovoked attack.
Posted to Twitter by music manager Jerome Haye, the video shows two police officers riding motorbikes down a street in Ilford in front of a police car.
Suddenly, after they're stopped by traffic, a pedestrian steps forward and pushes one of the officers, causing the bike to fall over and momentarily trap the rider.
However the officer is quick to recover and clambers over the fallen bike to chase the pedestrian on foot.
Another uniformed officer then appears from off-screen and joins in the chase.
Mr Haye shared the clip on Twitter, saying "@metpoliceuk getting pushed to their limits".
It was originally part of a Snapchat story, with the witness writing: "Can't believe what I just witnessed".
The Metropolitan Police has not commented on the matter.