For legal and practical purposes, a security guard is simply a civilian like anybody else. In fact, a more accurate term for their job might be “watch person” because a security guard’s main job is to watch what goes on around them and hence to deter people from doing anything they shouldn’t.
Sometimes, however, security guards do need to interact with the public, so here is a quick rundown of the relevant laws.
Security guards can use surveillance equipment, but remember GDPR
These days, it is increasingly common for businesses to have a central control room in which security guards use surveillance equipment (such as CCTV), plus guards walking around the area. Often the guards in the control room monitor the entire space; looking for issues, and send the guards on the floor anywhere they are needed.
This can work very effectively; just remember that a person’s biometric data is considered personal data under GDPR. In simple terms, this means that data can only be collected with informed consent and that the extent of the data collection must be proportionate to its purpose.
The use of facial-recognition technology is currently a legal hot topic and anyone interested in using it should do their own research thoroughly at the time and make sure to keep informed of any legal changes.
Furthermore, beyond the legalities, it might be a good idea to think about how it would be viewed by legitimate customers.
Security guards cannot undertake unauthorized searches of personal property
Security guards can undertake searches of property which has been left unattended in suspicious circumstances. In these situations there is no clear owner from whom to ask permission.
They cannot undertake unauthorized searches of personal property unless the person to whom it belongs (or appears to belong) is incapacitated and they are trying to identify and/or otherwise assist them.
Security guards can carry handcuffs but not weapons
In principle, security guards can carry and use handcuffs, although there are only very limited circumstances in which they can be safely used. In practice, handcuffs need to be put on correctly to avoid injuring the person on whom they are used and opening up the company to civil action on health-and-safety grounds.
Security guards can detain people, but can only use “reasonable force” to do so
This is probably the trickiest part of the law as it applies to security guarding. In the UK, anyone can make a “citizen’s arrest”.
The grounds for doing so are that someone is committing a crime OR that you have reasonable grounds to suspect that they have committed a crime AND that either it is impractical for a police officer to arrest them OR that you believe that the arrest is necessary to prevent harm to person or property.
Security guards can only use “reasonable” force to make the arrest, which for practical purposes essentially means “minimal” force. The practical issue here is not necessarily determining the amount of force which is reasonable; it’s being able to demonstrate that security guards did not use excessive force. Ideally, you would like to have an objective record of the process (e.g. body-cam footage) and not rely on witness testimony.