A Complete Guide to Using Knife Arches in Schools in the UK

In recent years, schools across the United Kingdom have increasingly turned to knife arches—also known as walk-through metal detectors—as a practical measure to combat knife crime and improve safety on school premises. Once seen primarily in airports and high-security venues, these devices are now seen on campus at schools and colleges around the country.

What Are Knife Arches?

Knife arch is a synonym of walk-through metal detector which is generally only used in the UK as our primary concern is knife crime and not gun crime like most countries. Knife arches are designed to quickly identify whether someone is carrying a metallic object such as a knife. Advanced models will have adjustable sensitivity that allows you to calibrate your search profile to accurately target the threat you are concerned about.

Knife arches are a tool of efficiency. They allow school staff to search hundreds of students quickly vs dozens using a traditional search wand or pat down as the primary search method.

Why Are Schools Using Knife Arches?

Knife arches serve a dual function. On one hand, they allow schools to detect weapons on school grounds and remove the threat by catching them before they are brought into the actual school.

The other function is to act as a deterrent that instils in students the understanding that if they try and carry a knife in to school, they will be caught. Studies have shown that in making a value calculation on whether to commit a crime, perpetrators place a much higher emphasis on the risk of being caught than the punishment for being caught.

Legal Framework for Knife Arches in Schools

Under the Education Act 1996 (Section 550ZA), headteachers and authorised school staff have the legal right to search pupils for prohibited items, including weapons, without consent, if they have reasonable grounds. This extends to screening pupils using electronic detection devices (knife arches and handheld search wands) without specific suspicion.

Searches should always be carried out by authorised staff members, with clear respect for the dignity and rights of pupils. Any discovery of a weapon must be reported to the police. Schools are advised to maintain clear records and follow their safeguarding and disciplinary policies.

How are Knife Arches Deployed at Schools?

Schools generally do not have the same resources as venues or secure locations which means that they do not have the capacity to search every student, every day. This means that a lot of institutions will do random spot searches.

Spot searches can take one of three forms. You can have a spot search on randomised days of the week where you search every student on that day. You can also have a knife arch setup every day and select random students to search. This is normally done with a search randomiser. Finally, you can have a knife arch setup on random days and randomly select students to minimise the burden on faculty and staff.

In many cases, a school will opt for a portable knife arch, like the RISK P1, over a fixed position model. This means that they can setup a search station quickly at the desired location when they wish to do searches rather than has a permanent setup.

What does a school knife arch search station look like?

There will normally be four parts to a school search station. You will have the knife arch for the primary search, a search randomiser, a table for search trays with divested items and a search wand for the secondary search.

Students will line up like normal and come into school with a teacher moving down the line pressing a search randomiser. If the randomiser displays search, the student will join the search queue.

Students in the search queue will approach the search station, remove everything from their pockets and place them in a search tray. The tray is then move from one side of the table to the other for collection after the search.

The student then passes through the knife arch which will either alarm or it will not. If it does not alarm, the students moves through, collects their divested items and is then clear to enter. If the knife arch does alarm, then the student is moved to the secondary search station where they wanded down by a member of staff using a search wand.

What are Search Wands?

As mentioned above, knife arches are tools of efficiency. Search wands are more tools of effectiveness. Doing a full wand search takes longer than walking through a knife arch which means that wanding every student is impractical. Search wands are used closer to the target metal which makes them more effective at detecting smaller masses, depending on the model you use.

It is for these reasons that search wands are best used in concert with knife arches rather than by themselves for schools. Nightclubs will favour full wand searches as they have the manpower to do them, whereas schools will tend toward the walk-through option.

Search wands come in a wide range of types and prices with the most popular model globally being the Garret Super Scanner V.

What are Search Randomisers?

Also known as random search selectors, search randomisers are simple devices that alternate between two or more options based on a preselected probability. In practice this means that the user presses a button on the device and then an LED will either flash on a pass or a search option.

If it flashes pass, then the target is not searched. If it flashes search, then the target is searched. In the context of the above search station arrangement. This would mean that students would queue up with a member of staff pressing the button and directing them to the search station if they are randomly selected.

This would remove accusations of bias and reduce the number of searches required. The probability that a search will occur can be adjusted to meet a school’s desired threshold for searches.

There are three main types of these devices, wall-mounted randomisers, handheld randomisers and clipboard randomisers.

Planning and Preparation - Policy Development

Review and Update Policies: Ensure your school’s safeguarding, behaviour, and search policies explicitly address the use of knife arches. These documents should define when and how searches are conducted, who is authorised to carry them out, and the procedures to follow if a weapon is found.

Legal and Ethical Oversight: Engage your safeguarding team and, where appropriate, your legal advisors or governors to review procedures. Ensure alignment with the Department for Education guidance on searching, screening, and confiscation.

Parental Communication: Notify parents and guardians in advance. Explain the rationale for using knife arches, how it enhances student safety, and outline the procedures. Offer opportunities for parents to ask questions or provide feedback.

Planning and Preparation - Staff Training

Designate Staff: Identify a team of staff members who will be responsible for overseeing knife arch operations. Ensure they are trained in the legal aspects of search procedures, safeguarding responsibilities, and the technical use of the equipment.

Practical Training: Staff should receive hands-on training in operating the arch, conducting handheld screenings, and responding to alerts. Emphasize respectful and non-confrontational interaction with students.

Safeguarding Protocols: Ensure all staff are familiar with safeguarding policies, particularly regarding how to handle disclosures, incidents involving weapons, and the need for discretion and sensitivity.

Planning and Preparation - Equipment and Setup

Acquire a portable, reliable knife arch. Verify that it complies with safety standards and is suitable for a school environment.

Supporting Equipment:

Security wand metal detector for follow-up scans.

Search Randomiser (if using one)

Search Trays or bins for personal items.

Secure storage for any confiscated items.

Clear signage explaining the process to students.

Setup Area:

Choose a location that supports orderly movement (e.g., a main entrance or a supervised hall).

Provide privacy if required for follow-up scans.

Ensure the area is accessible and free of obstructions.

Operational Procedures - Conducting Screenings

Briefing Students: Before any screening, inform students of the purpose and procedure. Reinforce that the aim is to keep everyone safe, and that the process is non-punitive and respectful.

Screening Process:

Ask students to remove metal objects from their person and place them in trays.

Students should pass through the arch one at a time.

If the arch activates, the student may be asked to undergo a secondary screening using a search wand metal detector.

Searches of personal belongings or a physical search of the student should only be conducted if legally permitted and with appropriate safeguards (e.g., two staff present, at least one of the same sex as the student).

Operational Procedures - Handling Prohibited Items

Confiscation: If a prohibited item (e.g., knife, blade, or other weapon) is discovered, it must be removed and secured immediately by staff.

Secure Storage: Confiscated items should be placed in a locked container and not handled unnecessarily.

Operational Procedures - Reporting and Documentation

1.) Report any weapon discoveries to the police without delay.

2.) Record the incident, noting the student involved, the item discovered, the time and date, and actions taken.

3.) Notify the designated safeguarding lead (DSL) and follow any internal safeguarding procedures.

Post-Operation Review

Debriefing: Meet with staff involved to review the operation, reflect on any issues, and discuss what went well. Identify opportunities to improve the process and update procedures as necessary.

Communication and Feedback: Inform parents of the outcomes of knife arch operations (e.g., “Thank you for your support, the screening was carried out safely and without incident”). Offer a channel for students and parents to provide feedback.

Policy Updates: Amend policies and procedures to reflect any changes based on operational learning. Ensure staff are made aware of these updates.