Not long ago, there was a notice at each end of the zebra crossing between London Bridge Walk and the station forecourt, improvised on blackboards, which said “DANGER – CROSSING OUT OF ORDER”. A friend enlightened me as to how a zebra crossing could be out of order: one of the belisha beacons had been knocked over by an errant vehicle. Apparently this means that the crossing is a legal nonentity. Drivers can mow you down on it with at least some impunity.
Incidentally, did you know that the belisha beacon was named after the transport minister who introduced it in 1934? His name was Leslie Hore-Belisha. So it could equally have been called the Hore beacon, but I imagine this was rejected on the grounds of ambiguity.