Last year, Ofsted investigated how schools, colleges and pupil referral units (PRUs) in London were dealing with knife crime and published a report. https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/785055/Knife_crime_safeguarding_children_and_young_people_110319.pdf
Knife crime may not seem high on the agenda in your organisation but have you staff had CPD on how to approach the topic with learners?
This website has some great case studies that can be used and educates about the risks of carrying a weapon https://www.knifefree.co.uk/
This set of videos is excellent for use in a staff workshop they are aimed more at schools but knife crime is not limited to school age children! The videos can be found here: https://www.lgfl.net/digisafe/survive