Abstract: A lock in which a key can neither be turned nor removed with the lock is open, is disclosed. The lock body is formed from two identical sections, the inner surface of each being provided with formations which accommodate the moving parts of the lock. The lock cylinder is provided with a plug which is operatively engaged to an extension. The lock shackle is engaged by a lock bearing which is held in place by the extension. Turning the key turns the plug and thus, the extension. This disengages the lock shackle as the lock bearing is no longer held in place. After it has been retracted, the contour of the lock shackle abuts the lock bearing, causing it to engage the extension, thus preventing the extension, the plug and the key from being turned.