The transport hierarchy in central London is simple enough.
The double decker buses are at the top of the food chain. The buses rule the roads. They don't care about anyone or anything in their way. The buses are out to get the cabs. The cab drivers are rude and in a hurry. They're trying to get past the huge buses. The cabbies are out to get the cyclists. The cyclists are everywhere. Scurrying left right and center. You don't see them until they're past you. The cyclists are out to get the pedestrians. The pedestrians. The lowly pedestrians are huffing and puffing their way down the sidewalks. They try to cross the streets without dying. Finally, the pedestrians are out to get the tourists, those people who decide to take painstakingly slow strolls at lunch and rush hours on Oxford Street and hold up the whole population.
And the tourists have no bloody idea of this whole mess.
Know your place and stick to it. Any deviants will not be tolerated. This is a well oiled machine my friends.