Will it tell you how to get a ticket for the tube? Last time I went to London I'd never heard of Oyster Cards (what you need) and couldn't find any staff anywhere, nor a single Lipstick Chick in white shades. It took me the best part of an hour to solve the mystery - (with thanks to the kind gentleman who patiently explained to the hick from the sticks). The previous time I was there you just put your money in and bought a ticket at a machine. I often wonder how the tourists manage, unless it's all a plot to get them to use taxis.
Edited to add: Oh, yes, by the way, I LOVE the photo.