What a private investigator can and cannot legally do in the UK

No powers, no licence, same law as everyone else

There is no statutory licence for private investigators in England and Wales. The Private Security Industry Act 2001 provides for one, but that part of the Act has never been brought into force, so anyone can call themselves an investigator. It follows that an investigator has no power of arrest beyond the one every citizen has, no power to demand information, no power to enter property, and no access to any record that is closed to the public.

What a competent investigator brings is method. Knowing which public sources hold what, how to observe someone lawfully for long enough to establish a pattern, how to record what was seen so that a court will accept it, and how to stop when the question has been answered. The value is in doing ordinary lawful things well, and in knowing which things are not lawful at all.

What an investigator can lawfully do

Observe people in public. Following someone on foot or by vehicle, watching an address from the street, and photographing or filming what is visible from a public place are lawful, provided the surveillance is proportionate to a genuine purpose and does not tip into harassment. Covert surveillance by a private firm is not regulated by the Regulation of Investigatory Powers Act 2000, which governs public bodies, but it is measured against the Human Rights Act 1998 when the evidence reaches a court, and against the Protection from Harassment Act 1997 at all times.

Search open sources. Companies House, the Land Registry, the electoral roll where it is open, court and insolvency registers, professional registers, press archives and anything a person has published about themselves online are all available to anyone. Open-source intelligence is the lawful backbone of most investigations. The UK GDPR still applies to how the results are collected, kept and used, which is why a genuine firm records a legitimate interests assessment before it starts.

Make enquiries openly. Speaking to witnesses, neighbours, former colleagues or anyone else who is willing to talk, while being honest about who is asking and why, is lawful. So is a discreet approach to a traced person that lets them decide whether to make contact.

Serve documents, take statements and give evidence. Personal service of court papers, witness statements in the form the court requires, and attending to be cross-examined on what the investigator saw are core parts of the work.

Verify what you have been told. Checking that a company exists, that a person holds the qualification they claim, that a property is owned by the person selling it, or that a CV matches the public record, all from sources open to anyone.

What is a criminal offence

The industry’s reputation rests on a handful of methods that are crimes, and any firm that offers them is offering to commit an offence on your behalf.

• Obtaining personal data by deception. Ringing a bank, a GP surgery, a utility or an employer while pretending to be someone else in order to extract information is pretexting, and it is an offence under section 170 of the Data Protection Act 2018. This is the route by which so-called phone records, bank statements and medical details have historically been sold, and it is prosecuted.
• Accessing accounts or devices without authority. Reading someone’s email, messages or social media, installing monitoring software on their phone, or guessing a password is an offence under the Computer Misuse Act 1990, whoever owns the device and whatever the relationship. Our guide on phone records and messages covers this in detail.
• Intercepting communications. Recording someone else’s calls or reading their post in transit is an offence under the Investigatory Powers Act 2016.
• Placing a tracker on a vehicle you do not own or control. There is no single offence named for it, but it engages the Protection from Harassment Act 1997, the data protection legislation and, where a spouse or partner is the target, the law on coercive control. A firm that offers to fit one to someone else’s car is a firm to avoid.
• Entering property, or going through bins on private land, without permission. Trespass is a civil wrong and, in some circumstances, a criminal one, and evidence obtained that way is likely to be excluded or to cost the client dearly when the court sees how it was gathered.
• Bribing a public official or an insider for information from a protected database such as police, DVLA, HMRC or benefits records.

Records no investigator can obtain

Whatever a website or a competitor tells you, there is no lawful private route to bank statements, phone bills, call or message records, medical records, DVLA keeper details, police records, tax records, benefits records, or the content of someone else’s email or messages. Where any of that is genuinely needed for a legal case, it is obtained by an order of the court on application by your solicitor. An investigator’s job is to build the lawful evidence that persuades a court to make that order.

How a court sees it

Civil and family courts in England and Wales rarely exclude evidence purely because of how it was obtained, but they punish improper methods in costs and they weigh the conduct of the party who commissioned them. The legal framework page on admissibility explains the balance. In practice, evidence gathered from a public place with a contemporaneous log and a clean chain of custody is admitted and carries weight. Evidence obtained by deception or intrusion may be admitted and still lose you the case on costs, and it may expose you and the investigator to prosecution.

Telling a lawful firm from an unlawful one

The reliable signs are in what a firm is prepared to promise. Our guide to choosing an investigator goes into detail, but the short version is this:

• A lawful firm asks why you want the information before it asks for the fee, and turns some work away.
• It tells you what it cannot get, without hedging.
• It puts the scope, the lawful basis and the fee mechanism in writing in an engagement letter.
• It will not quote a fixed price for “phone records”, “bank details” or “getting into” an account, because those are not lawful products.
• It expects to give evidence about its own work and keeps records that would survive that.

A firm that guarantees a result, works only in cash, or tells you that other investigators are simply less well connected is describing methods that will not survive contact with a court, and possibly a police investigation in which you are a witness or a suspect.

When an investigator is not the answer

If you are in danger, contact the police. If you need a record only a court can order, you need a solicitor first and an investigator second, if at all. If the question is whether a partner is unfaithful and there are no proceedings in prospect, the honest advice is often that surveillance will confirm what you already know at a cost that is emotional as well as financial, and that a conversation or a solicitor is the better first step. We say so when it is true.

This guide is general information about the law of England and Wales as we understand it at the date shown at the foot of the page. It is not legal advice and does not take account of your circumstances. Before acting on anything here, particularly where court proceedings, a criminal complaint or an employment decision are involved, take advice from a solicitor. We are investigators, not lawyers, and we will say so if a question you bring us needs one.

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