Guerrilla stickers appear on Tube
10 October 2012 Last updated at 15:59 BST
Is it a new form of vandalism or a rebellion against too many signs?
So-called guerrilla stickers have been popping up on the Tube network and a professor at the London School of Economics believes it is a reaction from some passengers fed up of being treated like children.
Transport for London said it was technically illegal to post stickers and passengers were better served when the signs were left alone.