Literal street signage - I guess London is used to so many pedestrians from countries that drive on the other side of he street that they need to mark where people should look for oncoming traffic.
It isn't just foreign visitors. The 'country cousins' - which included me when I visited London - need to be reminded that some roads are one way and the traffic direction does not change at all pedestrian 'islands'. If you really want to blow your mind, look up the 'magic roundabout' in Swindon, Wiltshire. In general, there is a lot of information painted on British roadways.
I like the angle in this. If it was square on, the text would be the message. Here the various directional elements get more equal attention.