DOOR LOCK
The invention provides a locking apparatus for a door comprising a key wherein the key is engageable with a lock from a first side of the door to enable the door to be unlocked and wherein the card is subsequently only removable from its engagement with the lock at a second side of the door remote from the first side. The sides of a door relevant in describing the invention are the normal front and rear sides of a door as approached by a person walking up to a door rather than any sides which are effectively edges to be retained in a door jamb. The key may be in the form of a card. In a locking apparatus of the invention the key is preferably only removable once engaged in the lock when the door is again locked.