As ATCO two mentioned, the wind direction at EGLC and EGLL can quite often (several times a month on average) be blowing from completely opposite directions. It has a lot to do with the river and the tall buildings near to the docks. It tends to be more 09 vs 27L/R than 27 vs 09L/R. The wind direction at City is more critical than any other airport in the TMA due to the steep approach and short runway. Most aircraft can't take as much of a tailwind as they would elsewhere, and certain types and operators can not take any at all. It isn't unusual to switch runway 5 or 6 times in an hour when the wind is from the north or south.
Runway directions across the entire TMA also vary between each airport fairly often. It's quite surprising how different wind conditions can be across such a relatively small distance. Procedures have to work for all mixtures of runway direction in use.