Ceci n'est pas une pipe
Outside Baker Street station is a statue of the mythical Sherlock Holmes, complete with pipe. There's not much point me banging on about the area because as ever, the Diamond Geezer got there before me, so follow the link if you want to read up.
The title is an allusion to the Magritte painting. I wonder how many non-french speakers are aware of the double entendre? (warning - link contains foul language and descriptions of base acts) Was it deliberate? I think so.