The Outside World is the term for anything and everything outwith the Big Brother House. One of the main rules of Big Brother is that housemates can make no contact with anybody other than their other housemates and, when in the diary room, Big Brother. Housemates recieve no news from outside the walls of the house and are given no clue as to the public perception of the House or housemates.
Due to this rule, the Big Brother House is considered to be secluded from the entire world, making it a small world of its own. Anything that occurs outwith the House is considerd as going on in the Outside World.
This can be illustrated through the horror drama, Dead Set, which bases itself around the housemates being the only survivors in Britain of a deadly infection that turns the dead into zombies. As they live in the House and are not informed of the infection, they do not realise what disaster has happened until they climb the Big Brother walls and look into the Outside World, where hundreds of raging zombies are screaming at the housemates.
Any housemate who attempts to make contact with or receive information from the Outside World, during their stay in the house, will be ejected by Big Brother. If a housemate escapes the confines of the house and encounters the security staff, the housemates may leave permanently or go back in as they have not left the Big Brother house. If the public ever attempts to make any contact with the housemates by form of shouting, throwing objects or flying messages overhead, housemates are immediately ordered to enter the house and the garden is temporarily sealed off.