http://www.snopes.com/welcome-australia-sign-fake/ Of course, given that this is a digitally altered version of an already digitally altered sign purporting to be in Australia, given the cultural links between the Australians and the British and the politically motivated subject matter which only a British person would find amusing, the chances are that a British person added the "unles".
It's a joke, I find it funny, quite close to reality though isn't it! Why is there the need to put the British down as if we are sub human, are we not allowed to have a laugh, a laugh at ourselves after all?
The British was highlighted to contrast with @Aromulus implication that an American or Australian made the misspelt edit when indeed it was most likely to have a British person. That in itself is the real joke here since both the sign and the subsequent remark concerning spelling were both very British digs at johnny foreigner and not actually the British laughing at themselves..
