The information is not held in the form requested. Any incidents involving keys or locks, as reported from individual establishments, are recorded as one consolidated figure and this figure will include broken keys, damaged or sabotaged locks, incidents where prisoners or other unauthorised personnel may have had sight of or access to keys and incidents where staff had taken keys out of the establishment. To separate out those incidents where keys were missing or unaccounted for, for whatever reason, would involve disproportionate cost.