A locking system for securing, within a rectangular frame aperture of a safe, a hinged door having a perimeter and an external side and an internal side and occupying a first vertical plane, the door being configured for suspension on hinges. The locking system comprises a key axle, a disc, a plate. When the key axle is rotated the disc is caused to rotate and the plate slides horizontally to extend a distal end of the plate towards beyond the door perimeter.