UK security industry glossary
Plain definitions of the terms used in running a UK security company, with a link to the primary source where there is one.
Last reviewed 5 October 2026. General information, not legal advice.
Approved Contractor Scheme (ACS)
A voluntary scheme run by the SIA under which security companies are independently assessed against a set of operational and performance standards. Approval applies to the company, not to individual officers, and is separate from individual licensing.
Assignment instructions
The written, site-specific instructions that tell officers what their duties are at a particular client site, including patrol requirements, emergency procedures and contacts.
BS 7858
The British Standard for screening individuals working in a secure environment. It sets out a code of practice for pre-employment checks such as identity, address and employment history, typically covering a period of years before the role. Security companies commonly screen staff to it, and it is widely required by clients and approval schemes.
In GuardLink: Screening records are stored against the officer with an expiry date. The screening itself is done outside the product.
Check call
A routine contact at agreed intervals between a security officer and a control room or manager, confirming that the officer is safe and the site is in order. A missed check call is treated as a possible welfare issue and followed up.
In GuardLink: Check-ins are generated from each site's interval and a missed lone-worker check-in alerts managers.
DBS check
A criminal record check carried out by the Disclosure and Barring Service for roles in England and Wales. Scotland and Northern Ireland have their own bodies, Disclosure Scotland and AccessNI.
In GuardLink: DBS certificates are stored as documents with an expiry or review date.
Door supervision
Manned guarding carried out at licensed premises open to the public, such as pubs, clubs and events where alcohol is served. It requires a door supervisor licence, which also covers general security guarding.
Geofence
A virtual boundary around a real location. In attendance systems it is used to accept a clock-in only when the phone reports a position inside the boundary.
In GuardLink: Sites can have a geofence that refuses clock-ins from outside a set radius.
Guard tour (patrol checkpoints)
A planned sequence of points an officer must visit during a patrol, with a record of when each was visited. Guard tour systems replace paper patrol sheets with a time-stamped electronic record.
In GuardLink: Checkpoints are sequenced and time-windowed, and each is confirmed with a photo and a GPS-stamped record.
Key holding
Holding keys or access devices for a client's premises and attending when needed, for example after an alarm activation. Key holding is a licensable activity when provided under contract.
Lone worker
Someone who works by themselves without close or direct supervision. UK employers have the same health and safety duties towards lone workers as towards other staff and are expected to assess and manage the particular risks of working alone. Many static night-shift and mobile patrol officers are lone workers.
Manned guarding
Security provided by officers physically present at a premises, guarding against unauthorised access, theft or damage. It is one of the licensable sectors regulated by the SIA.
Mobile patrol
A security service in which an officer visits one or more sites at intervals during a shift, checks agreed points, and records each visit, instead of staying at a single site.
Security workforce management software
Software that combines the rota, compliance records, attendance, patrol and welfare records, and pay and billing data for a security company, so that each depends on the others instead of being maintained separately.
SIA licence
A licence issued by the Security Industry Authority, the regulator of the UK private security industry. Under the Private Security Industry Act 2001, individuals carrying out licensable activities such as manned guarding, door supervision, close protection, CCTV operation, cash and valuables in transit, and key holding must hold the appropriate licence. Licences are issued to the individual and expire, so they must be renewed.
In GuardLink: Each officer's licence expiry is recorded and tracked, and an expired licence blocks shift assignment.
TUPE
The Transfer of Undertakings (Protection of Employment) Regulations 2006. When a security contract moves from one provider to another, the officers assigned to it usually transfer to the new provider on their existing terms.
Working time limits
The Working Time Regulations 1998 set limits including an average 48-hour working week (which workers can opt out of in writing), a daily rest period of 11 consecutive hours and a weekly rest period. Night workers have additional limits.
In GuardLink: Scheduling blocks assignments that leave less than 11 hours' rest and warns above 48 hours in a week. These are aids for the scheduler, not a record of compliance.
Licence tracking, check calls and working-time checks, built into one system.
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