Inspired by the "The North?..." thread.
Don't you find it odd that you can be driving along a minor A road or something in London and see a sign reading "Elephant and Castle, Brixton...Portsmouth". Or say, Manchester with a sign like "MEN Car Park...Glasgow...".
I get this if you are on a major A road that is actually heading in that direction but it appears to me sometimes these sings are random and even though you COULD get to glasgow by heading in that direction you'll see another sign coming from a different direction, heading the other way, pointing to that same city.
So basically these signs are just telling you to leave the city in every direction and eventually you'll end up in another one.