As can be seen from the video, the thief is astride the motorcycle of the women and is trying to get off on it. At the same time, the women, in an attempt to get her bike back, gets a smack on her helmet by the bare hands of the robber and gets her helmet visor dropped on the floor.
The attempt failed when two strangers standing aside, witnessing all this drama, jumped into the scene and tried to banish the robber. Two companions of the culprit were standing at a distance on their scooters and ran away while they were joined by their teammate who, got off the bike, and flew away.
In previous two years, robbing of motorcycles has risen to over 600 % in London which is resulting in a tensed situation within decent riders. Various such chaos has been reported many times, videos of which get viral on youtube. In many such incidents, strangers passing by the scene either stand still and watch the injustice happening or just walk off the place. These two citizens, after helping the victim escape from such misfortune, have shown a great example of humanity.