the internal lock mechanism not shown contained therein a mounting bracket 30 for the lock casing 28 provides an enclosure in which the plate 10 is mounted in one recognized method of attempting to gain unauthorized access to the safe the lock dial 22 is knocked off the spindle 24 which is then hammered into the lock casing 28 such that the spindle 24 is driven into and dislodges the lock casing cover 29 a drilling attack then commences on the safe door 26 and the plate 10 until access has been gained to the interior of the lock casing 28 a number of holes will normally have to be drilled to gain sufficient access to the lock mechanism and the limited space will normally require that the holes are drilled one at a time typically a first operator equipped with a power drill will crouch in front of the safe door while a second operator pushes the first operator towards the door to provide a load on the drill once the necessary holes have been drilled further hammer attacks on the lock mechanism inside the casing 28 may then serve to disengage the lock and allow the door 26 to be opened reference is now made to fig3 of the drawings which shows a lock 36 fitted with a hard plate 40 according to the present invention the parts of the lock 36 in this figure are generally similar to those shown in fig2 however in this instance the hard plate 40 has a convex outer surface 41 further the plate 40 the lock casing 46 containing the lock mechanism 47 and the lock mounting bracket 48 are circular such that the.