GPS Trackers, Surveillance and Stalking: Understanding the Legal Boundaries for Private Investigators
Recent reports within the private investigation industry have highlighted the arrest of an investigator on allegations of stalking offences.
While every case turns on its own facts and allegations should never be prejudged, it serves as a valuable reminder that surveillance work must always be underpinned by clear legal justification, careful planning and professional judgement.
For reputable investigators, this should not be a cause for concern but rather a timely opportunity to revisit the principles that distinguish lawful investigation from conduct that risks crossing legal boundaries.
Stalking and Surveillance Are Not the Same Thing
The offence of stalking is contained within the Protection from Harassment Act 1997, as amended by the Protection of Freedoms Act 2012. In simple terms, stalking involves a pattern of unwanted and repeated behaviour directed towards an individual that amounts to harassment.
Examples may include:
Following or monitoring an individual.
Attempting repeated contact.
Watching or spying on someone.
Monitoring online activity.
Loitering near a person's home or workplace.
Interfering with property.
Using tracking technology.
Importantly, none of these activities are automatically unlawful in isolation. Context, purpose, necessity and proportionality are all critical factors.
There Is No Automatic Exemption for Private Investigators
One misconception encountered from time to time is that licensed or professional investigators somehow enjoy immunity from stalking legislation. They do not.
Private investigators remain subject to exactly the same criminal and civil laws as everyone else.
The Protection from Harassment Act provides statutory defences in certain circumstances, including where conduct is carried out:
for the prevention or detection of crime;
under an enactment or rule of law; or
where the conduct was reasonable in the particular circumstances.
Whether those defences apply will always depend upon the individual facts of the case.
Due Diligence Starts Before Surveillance Begins
Professional investigators should never simply accept instructions at face value.
Before any deployment, it is good practice to establish:
Who is instructing the investigation?
Do they have a genuine and legitimate interest?
Is the objective lawful?
Is surveillance genuinely necessary?
Is there a less intrusive way of achieving the same result?
Is the proposed deployment proportionate?
Robust client vetting protects both the investigator and the client.
For example, an investigator should be extremely cautious where an instruction appears designed to circumvent family court proceedings, non-molestation orders or other legal protections.
The Importance of Proportionality
Professional surveillance should always be proportionate to the objective being pursued.
A short period of observation in a public place may be entirely reasonable in one investigation, whereas prolonged monitoring of a person's home or repeated attendance at their address could become difficult to justify.
Every operational decision should be capable of answering a simple question:
Why was this necessary?
If that question cannot be answered clearly and objectively, the deployment may require reconsideration.
GPS Trackers: One of the Industry's Grey Areas
One topic that continues to generate discussion within the investigation industry is the use of covert GPS tracking devices.
Some commentary suggests that attaching a tracker to another person's vehicle is automatically a criminal offence. Equally, others suggest that it is always permissible provided there is a legitimate investigative purpose.
The reality is more nuanced.
There is no blanket legal exemption allowing investigators to deploy GPS trackers simply because they are conducting surveillance. Equally, there is no single criminal offence that makes every use of a tracker unlawful.
Instead, several areas of law may become relevant depending upon the circumstances, including:
trespass to land;
trespass to goods;
data protection and privacy obligations;
harassment or stalking legislation; and
the overall reasonableness of the investigator's conduct.
This is particularly relevant in matrimonial investigations, where clients may seek evidence of infidelity. While the client may believe they have a legitimate interest, that does not automatically justify every investigative method available.
Each deployment must be assessed on its own facts, taking into account necessity, proportionality and the availability of less intrusive alternatives.
Planning Protects Everyone
At FIND, every surveillance deployment is subject to structured planning and risk assessment before any operative is instructed.
We apply recognised decision-making principles to ensure every investigation is:
Proportionate
Lawful
Appropriate
Necessary
Documenting these considerations creates a clear audit trail demonstrating why surveillance was justified and how decisions were reached.
Good operational planning does not guarantee that an allegation can never be made. However, it provides strong evidence that decisions were taken responsibly, professionally and within a recognised legal framework.
Professional Investigation Demands Professional Judgement
Surveillance is a legitimate investigative tool when used responsibly.
The challenge for investigators is not simply asking whether something can be done, but whether it should be done.
Every instruction deserves careful scrutiny. Every deployment should be capable of objective justification. Every investigator should be prepared to explain why their actions were necessary, proportionate and lawful.
Ultimately, professionalism is measured not by the technology we use or the evidence we obtain, but by the judgement we exercise before an investigation even begins.
