This is the link on the UK government website
https://www.gov.uk/hand-luggage-restrictions/work-tools , spanners and wrenches not allowed in hand luggage.
Where this fell down is the customer service of perhaps helping the guy check-in his luggage. The security team had no choice, and they would be hammered
if they let it through as the CAA are continually monitoring airports with visits almost every week. Also believe that there is a full tender process underway for the
contract.