The Citizens Advertising Takeover Service (CATS)

With your help, we're going to replace every single advert on a London tube station with pictures of cats.

Useless? yes.
Fun? yes.
Involves our Feline Overlords? yes.
I've pledged. (just 1£, because it *is* useless, and I'm not even going to see the results, since I don't think I'll be in the London tube in the nearby future)