Why Do Private Investigators Follow People?

July 16, 2021 - Reading time: 10 minutes
Updated on: August 7, 2025

As private investigators, our work is often misunderstood and fictionalised by popular TV shows and movies… The reality is that private eyes work across the UK (and most countries!) on a daily basis. Some people may even develop fears that private investigators might be following them, however, PIs will only follow people for good reason.

There are many different reasons which might cause a private investigator to follow you, from an accident injury claim investigation, to an investigator instructed by your partner and anything in-between. Private investigators do not simply follow people out of their own free will – they do so because they receive instructions from their clients. We will explore some of the most common reasons for private investigators to follow people in this article.

1. Accident injury claims

Accident injury claims are one of the most common reasons for private investigators to follow people. With an abundance of “no win no fee” law firms operating across the UK, pursuing litigation is often easy and costless for claimants, and the temptation for them to exaggerate or fabricate their injuries is ever-present.

With stakes running high, it is often a cost-effective decision for insurance companies to instruct private investigators to follow people and examine their injury claims. If, for example, a subject claims that they are not able to walk unaided, and that same person is later photographed by a private investigator playing football, then they may find it difficult to explain the evidence which is gathered.

If you are making an injury claim then you should expect that a private investigator may examine your claims and verify their accuracy.

2. Infidelity investigations

Infidelity and accident injury investigations are by far our most common reasons for conducting surveillance on an individual. If your partner suspects that you might be cheating on them, then they may decide to check your activities by hiring a private investigator to follow you and check on your movements.

Most people that are cheating on their partners would never suspect that a private investigator will get involved and be asked to follow them – it is usually the last thing on their minds. If you suspect that your partner is having an affair but are unable to prove it, then gathering hard evidence showing their activities can be very rewarding in most cases.

When a marriage breaks down due to infidelity and a couple parts ways, then the stakes can be even higher, and the cost of hiring a private investigator can often be earned back a thousand times over if it helps to swing a divorce settlement in one party’s favour.

3. Investigating sick employees

When an employee claims that they are too unwell to work, they might receive statutory sick pay from their employer. If their claims are genuine then the firm should have no issue in compensating their employee. However, not all people are as honest as we might hope.

False claims of this nature can wind up costing small fortunes, with the costs particularly damaging to small and medium size enterprises.

If a company suspects that their employee is being dishonest about their health in order to receive sick pay, then hiring a private investigator to place that individual under surveillance can be a cost-effective solution to the problem in most cases.

If, for example, an employee is claiming to be bedridden, but is subsequently photographed by a private investigator playing golf for several hours, then they might find their claims difficult to maintain. Protecting a company’s interests by checking on sick employees can help to save significant amounts of money.

4. Character checks by a concerned relative

What do we mean by “Character checks by a concerned relative”? Well, if a close family member begins a romantic relationship with a certain person that you have a concern about, then a private investigator can help by placing that person under surveillance and checking their lifestyle.

It should be noted that in most cases of this type, a background check would be the most common solution provided by us. However, if our client wishes to take things a step further than a simple background check, then we can also help to place the subject under surveillance and check their movements. Often is the case that our clients will ask to include personal surveillance in addition to our background check service.

In such cases we always recommend running checks or performing surveillance as soon as possible after a relationship starts to become serious… The more time that passes, the stronger feelings can become, and we find it’s better to perform due diligence from the outset.

5. Cohabitation investigations

There are many different reasons that we might be instructed to start a cohabitation investigation. Most commonly, we will be asked to gather evidence of cohabitation for use in a case related to matrimonial maintenance payments (typically post-divorce), in financial or divorce settlement cases, and in child custody cases.

We often work alongside solicitors for cohabitation investigations, though we equally happy to accept instructions from private individuals.

Local authorities also commonly rely on private investigators to gather proof of cohabitation for investigations into potentially fraudulent benefit claims.

Investigations into cohabitation can often span over several weeks or even months, as our clients will typically need to document a subject’s living circumstances beyond any doubt.

6. Hostile surveillance and malicious intent

While most surveillance work is carried out for legitimate purposes, it's important to understand that not everyone uses surveillance ethically. In some rare cases, individuals with dishonest or malicious intent may attempt to use private investigators under false pretences. For example, someone with personal grudges or controlling tendencies may present a false narrative to a private investigator in order to justify following someone. If the investigator isn’t aware of the full context or is being deliberately misled, they may unintentionally participate in what is essentially malicious surveillance.

Hostile surveillance isn’t always carried out by licensed investigators either. Criminals, stalkers, and others with bad intentions may observe your movements in order to plan robbery, assault, harassment, or worse. In rare but serious cases, even terrorists may conduct surveillance to identify potential targets or security weaknesses.

7. Counter-surveillance and bug sweeps

If you believe you may be under surveillance-whether by a private investigator, a malicious actor, or someone else-you may want to consider hiring professionals who offer counter-surveillance services. These services can help identify if you are being followed or monitored, and can involve a mix of physical and electronic checks.

A common solution is a bug sweep, also known as Technical Surveillance Counter-Measures (TSCM). These sweeps detect hidden devices such as microphones, GPS trackers, or covert cameras that may have been placed in your home, car, or office. We also offer this service as part of our wider counter-surveillance work, so if you’re feeling suspicious, we can help you get to the bottom of it.

Counter-surveillance might involve:

• Monitoring whether you're being followed or watched
• Electronic scanning of your home or car for hidden devices
• Providing guidance and evidence if ongoing surveillance is discovered

8. What to do if you think you're being watched

If you feel you're being surveilled and it's causing you concern, there are some practical steps you can take:

• Don’t confront or panic-keep calm and start taking notes
• Document suspicious vehicles or people who repeatedly appear
• Get in touch with a private investigator who specialises in counter-surveillance
• Consider having a bug sweep carried out to check your property and possessions

Not all surveillance is lawful or justified. If something doesn’t feel right, you’re well within your rights to investigate and protect yourself.

Static surveillance or mobile surveillance

When it comes to surveillance, there are usually two different services offered by us: Static surveillance or mobile surveillance. As part of “Mobile surveillance” the agent will remain mobile and actively follow the subject as they travel around. Mobile surveillance can be conducted on foot, using public transport, or using vehicles (usually cars), depending on the subject in each case and how they are likely to travel around.

Static surveillance on the other hand would involve the surveillance agent remaining outside a specific property and photographing subjects as they come and go from the address.

Both forms of surveillance hold their own advantages and the best course of action will always depend on the circumstances in each case and our clients’ goal for the investigation.

Private Investigators UK

We are a leading private investigation firm based in the UK and provide surveillance services nationwide. For more information about PrivateInvestigators-UK, our services, and our fees, please click through to our homepage, or continue browsing our blog for more free private investigator resources.

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