When the passenger manages to rip the knife from the clutches of the alleged assailant, the man sprints out of the bus's back doors and down the pavement towards a BP petrol station.

A shocked woman can be seen stepping off the bus and pointing at the passenger as she cries that he has been cut.

The camera then pans to the man who is now holding what appears to be a kitchen knife, and has blood coming out of several gashes on his wrist and hand.

The footage comes as Scotland Yard warned Britain has been hit by a surge in violent crime.