To be totally honest, I wonder if London gets any fog anymore. We used to get some hellish stuff in Glasgow - I can remember wheeling the bike because I couldn't see the road, and as I got older I can remember driving home by following the tramlines - a cool sense of navigation that depended on intimate memory of where the branches were. Had that been today, I wouldn't even remember where I was supposed to be going, never mind where the trams might choose to venture.
But, I suspect it wasn't really fog, but smog, the product of the coal age. How we lived. If we lived.
Rob C