How to Hire a Private Investigator in the UK (and Is It Legal?)

By Nathan, former police Detective Sergeant, Full Member of the Association of British Investigators and Certificated Enforcement Agent · Reviewed September 2026

Yes, it is legal to hire a private investigator in the UK. The industry is not licensed, so the investigator you choose has to follow the same laws as everyone else, and the safest way to hire one is to check they are a member of the Association of British Investigators and registered with the Information Commissioner’s Office.

This guide covers the legal position, why the lack of licensing matters more than most people realise, what a private investigator can and cannot do for you, how the cost works, how to hire one step by step, and what to ask before you instruct anyone. It is written from the law of England and Wales, which is where we work. Scotland and Northern Ireland differ on some points.

If you would rather talk it through, we’re on 0114 438 7077 seven days a week, 8am to 9pm, and the conversation is confidential.

Is it legal to hire a private investigator in the UK?

Yes. Any private individual, employer, landlord or solicitor can legally hire a private investigator. What the law controls is not the hiring but the investigation itself: how evidence is gathered, how personal data is handled, and whether the subject’s rights are respected.

Responsibility for working lawfully sits with the investigator. A reputable private detective will tell you at the first conversation whether what you are asking for can be done legally, and will decline the parts that cannot. The simplest rule we give clients is this: never ask an investigator to do something you could not lawfully do yourself. A PI has no special powers. What a good one has is training, time, equipment and the discipline to gather evidence that will survive scrutiny in court.

What does a private investigator do?

A private investigator gathers information and evidence lawfully on behalf of a client, using surveillance, tracing, research and interviews. The work is confidential, and what you receive at the end is a written report with supporting stills, unedited video or documents, prepared so it can be relied on in family, civil, employment or criminal proceedings.

The cases we handle most often at Dolos Investigations are:

• Surveillance, static or mobile, to establish where someone goes and who they meet, with a contemporaneous log kept throughout.
• Cheating partner investigations, where you need certainty rather than suspicion.
• Tracing people and background checks, including missing family members, birth parents, debtors and witnesses, and due diligence on partners, suppliers or hires.
• Child custody and contact investigations, gathering evidence about a child’s welfare during contact with another party.
• Fraud investigation, including false sickness or injury claims and employee misconduct.
• Process serving of court documents, with proof of service, in Sheffield, Manchester, Leeds and London.
• Bug sweeps of homes, vehicles and offices for covert cameras, listening devices and trackers.
• Vehicle tracking, deployed within a lawful framework as part of a wider surveillance instruction rather than as a gadget rental.
• Polygraph testing for relationship disputes and workplace investigations. Polygraph results are not generally admissible in court in England and Wales, and we will say so before you book one.
• Support for solicitors, including witness tracing, statement taking and evidence gathering for litigation.

We also provide commercial enforcement services for landlords, which most private investigation firms cannot, because the principal is a Certificated Enforcement Agent.

How is a private investigator different from the police?

A private investigator works for you, not the state. We have no powers of arrest, no right to demand information, and no access to police or government databases. The police investigate crime in the public interest and set their own priorities. A private detective investigates what matters to you, on your timescale, within the same law that applies to everyone.

Having led covert investigations as a Detective Sergeant, I can tell you the standard of evidence is no different. A court does not care whether a photograph was taken by a police officer or a private investigator. It cares whether it was obtained fairly, proportionately and lawfully. That is why our methods are built around the same necessity and proportionality tests I applied in the police.

Are private investigators licensed in the UK?

No. There is no compulsory licence for private investigators in the UK. The Private Security Industry Act 2001 defines private investigation as an activity that can be licensed by the Security Industry Authority, but the Government has never switched that requirement on. In 2013 the Home Office announced that operating without a licence would become a criminal offence from the following year. It did not happen. When asked under Freedom of Information in 2022, the SIA confirmed that no regulation has been proposed or implemented and that it has no plans relating to the regulation of private investigations.

How UK private investigator licensing stalled

That means anyone can call themselves a private investigator, print business cards and start taking money. It also means the checks you make before hiring are the only safeguard you have. In practice, professional membership has stepped into the gap the law left. Here is what to look for instead of a licence.

Membership of the Association of British Investigators. The ABI is the only body in this industry recognised by the Law Society of England and Wales, which recommends it to solicitors. Membership is not a formality. The table below sets out what the ABI actually checks before it admits a Full Member.

What ABI Full Membership checks

Source: ABI Full Membership criteria. Dolos Investigations is a Full Member.

Registration with the Information Commissioner’s Office. Under the Data Protection (Charges and Information) Regulations 2018, organisations that use personal information, including sole traders, must pay a data protection fee unless exempt. An investigator handles personal data on every job. If they are not on the register, they are either unaware of their obligations or ignoring them. You can search the ICO register yourself in under a minute.

A verifiable professional background. Former police officers, military investigators and people with formal investigative qualifications can all evidence their training. Ask what it is and check it.

Written terms, a data protection notice and insurance. A legitimate investigator will have all three and will not be offended when you ask. We carry professional indemnity and public liability insurance, and our terms and conditions are published.

What laws do private investigators have to follow in the UK?

Private investigators are bound by the general law, and several pieces of legislation bear directly on how an investigation must be run. These are the ones that matter to you as a client.

The laws that govern a private investigation in England and Wales

The last row deserves a word of explanation, because our old version of this page got it muddled. RIPA does not bind private investigators. Nothing in the Act requires us to seek an authorisation before conducting surveillance. But the reason public bodies have to show necessity and proportionality is that courts expect it of anyone whose evidence intrudes on a person’s private life. Working to that standard is the difference between evidence a judge accepts and evidence a judge throws out. It is also the standard I worked to for years in the police, so it is not a stretch to keep to it now.

What a private investigator cannot legally do

• Access phones, email, social media or computers without authorisation, or install spyware.
• Intercept calls, texts or messages.
• Obtain bank, medical, phone or benefits records by deception.
• Enter private property without permission.
• Impersonate a police officer or any other official.
• Fit a tracker to a vehicle without a lawful basis to track it.
• Harass, intimidate or repeatedly follow someone with no legitimate purpose.

If an investigator offers any of these, walk away. The evidence would be worthless in court and you could be prosecuted alongside them. Our article on whether private investigators can access someone’s phone goes into the most common of these in more detail.

Can you hire a private investigator to follow someone?

Yes, lawful surveillance of a person in public places is legal in the UK when there is a legitimate reason for it, such as gathering evidence for family, civil or employment proceedings. It becomes harassment or stalking when it is persistent, intrusive, or has no proper purpose behind it.

The question we are asked most often is some version of “can I have my ex followed?”. The honest answer is: only if there is a genuine legal reason. A child custody dispute where the child’s welfare is in question, or a financial settlement where hidden assets are suspected, can both be legitimate reasons. If the motivation is to know where they are, who they are seeing, or to make them feel watched, no reputable investigator will take the instruction. We screen every request against that test, and we turn work away. Our terms restrict instructions to lawful purposes, and we will not take on anything that could help someone locate a person who has left them for their own safety.

Two related questions come up. Will the subject find out? Professional surveillance is designed not to be detected, but nobody can promise it, and once a subject knows they have been watched, doing it again becomes far harder. Could the subject sue you for hiring an investigator? Only if the law was broken, for example through harassment, unlawful data processing or trespass. That is one more reason to hire someone who works inside the law.

When should you hire a private investigator?

You should hire a private investigator when you need reliable evidence or information that you cannot lawfully or practically obtain yourself, and when the outcome matters enough to justify the cost. These are the situations where instructing one makes sense.

1. Suspected infidelity. A private detective can confirm or rule out suspicions discreetly, so that decisions about a relationship, a divorce or a financial settlement rest on facts. Some clients find out their partner has been faithful all along. We will tell you either way, and we will show you the evidence.
2. Missing people. Long-lost relatives, birth parents, beneficiaries of a will, debtors who have moved without leaving an address, and witnesses needed for a court case can all be traced through lawful research and enquiries. Success depends on how much you know to start with, and we will tell you honestly how likely a trace is before you commit.
3. Background checks. Before appointing someone to a position of trust, or before entering a business relationship, a proper check verifies identity, history and the claims a CV or a website makes.
4. Employers and workplace investigations. Employers can lawfully instruct an investigator to look into suspected misconduct, fraudulent sickness absence, theft or breaches of contract, provided the investigation is proportionate and complies with data protection law. This is the scenario where doing it badly does the most damage: an internal investigation with no evidential discipline frequently turns a small problem into a tribunal claim.

How this works in practice: a building services company has an employee signed off with a back injury for eleven weeks, and two colleagues have separately mentioned seeing him working on other sites. The company has hearsay and nothing else. It instructs a fixed number of surveillance hours over specific days, agreed and priced in advance. The work is carried out covertly, with a contemporaneous log, stills and unedited video prepared for a disciplinary hearing or tribunal. Nobody inside the company beyond the instructing directors knows about it. Whatever the surveillance shows, the company then acts on evidence rather than rumour, including dropping the matter entirely if the employee’s account holds up. This is an illustration of how an instruction works, not a description of a specific case.

6. Landlords. Tenant checks, suspected subletting, abandoned properties and rent arrears all benefit from an investigator who can establish the facts before legal action. Our guide to background checks on a tenant covers what a landlord can lawfully find out.
7. Business partners and due diligence. Before investing in, buying or merging with a business, an investigation into the people behind it can reveal undisclosed directorships, insolvencies or litigation.
8. Solicitors and legal cases. Process serving, witness tracing, statement taking and evidence gathering for civil and criminal matters. Our reports are prepared with court use in mind, and instructing solicitors can receive the material directly.
9. Child custody disputes. Where a child’s living conditions or care during contact are in question, independent evidence can carry real weight with the court.
10. Corporate fraud and espionage. Leaked information, competitor collusion and internal theft often need covert investigation to prove.

When you should not hire a private investigator

• When there is no legitimate purpose beyond curiosity or control.
• When a crime is in progress or someone is at risk. Call the police.
• When you want something done that is illegal. No investigator can make it legal.
• When a public search would answer the question. A social media check or a Companies House search does not need an investigator, and we will say so.
• When your expectations exceed what evidence can deliver. Surveillance can produce nothing, and that is itself information. We will tell you what an investigation can and cannot establish before you spend anything.

Is it worth it? It is when the answer will change a decision: whether to stay in a marriage, whether to proceed with a claim, whether to hire, whether to invest. We have written separately about the reasons you might not want to hire a private investigator, because not every suspicion needs investigating.

How much does it cost to hire a private investigator in the UK?

We charge a fixed hourly rate, agreed before any work begins, and we agree the number of deployment hours up front, so you know the total cost before we start. Mileage, parking and subsistence are included in the rate rather than added afterwards. The one exception is a deployment that involves a restaurant, which we discuss with you beforehand. Deployment is only ever extended on your say-so.

The total depends on the type of work, how many agents are needed, how many hours are involved, and how urgently you need the result. Surveillance is charged by the hour; two agents is our recommended minimum, and if your budget only stretches to one we will tell you what that realistically gets you before you commit. Tracing, background checks and process serving are quoted per instruction.

How much is a PI for a day? Because we quote in agreed hours rather than a flat day rate, the answer depends on the number of hours and agents your case needs. We will give you a written figure after a free consultation, and we will tell you if we think an investigation is unlikely to be worth the money.

On price, we are straight with people: we are more expensive than budget operators and cheaper than the largest regional firm. What the difference buys is a former police Detective Sergeant doing the work, real insurance, real professional membership, and evidence that will hold up. What it does not buy is a surprise invoice. You can read more about how our fees work, or call 0114 438 7077 for a figure.

How to hire a private investigator in the UK: step by step

Hiring a private investigator takes six steps. Follow them in order and you will avoid nearly every problem people have with this industry.

1. Be clear about what you need to know, and why. Write down the question you need answered and what you will do with the answer. Evidence for court, peace of mind, and a current address are three very different briefs.
2. Check the investigator is legitimate. Use the five-minute verification checklist below. If they fail any item, keep looking.
3. Have a free, confidential consultation. Be honest about the situation, including the parts that embarrass you. An investigator who does not know the full picture cannot plan properly and cannot tell you whether your request is lawful. We also check for conflicts of interest at this stage and decline instructions where we already act for the other side.
4. Agree the scope, method, agents, hours and cost in writing. You should receive terms of business and a data protection notice before any work starts. If you instruct us verbally, we confirm it in writing within two business days. Timescales are agreed at this point.
5. Let the investigator work. Do not contact the subject, do not post about it, and do not try to help by following them yourself. Interference is the most common reason surveillance fails.
6. Receive the report and have it explained. You get a written report with the supporting evidence, and we walk you through it verbally, step by step. Clients tell us that walkthrough is the part they value most. We explain exactly what follows in our guide to what happens after you hire a private investigator.

Five-minute verification checklist

Before you instruct anyone, do these five things. None of them needs a phone call.

What to ask a private investigator before hiring

Ask these questions before you instruct anyone. A professional will answer all of them without hesitation.

• Are you a member of the Association of British Investigators, and can I check?
• Are you registered with the ICO?
• What is your background, and what experience do you have with cases like mine?
• Who will actually do the work, and will I be able to speak to them?
• How will you gather evidence, and will it be admissible in court?
• What will it cost, what is included, and what could add to the cost?
• How and how often will you update me?
• How will my data and the subject’s data be handled, stored and deleted?
• Do you have professional indemnity insurance?
• Will you tell me if you find nothing?

Red flags to walk away from

• Guarantees of a particular result, or a published success rate.
• Offers to obtain phone records, bank statements or account access.
• No written terms and conditions.
• Cash only, or reluctance to give a business address.
• Pressure to decide today.

Why hire Dolos Investigations?

Dolos Investigations is run by Nathan, a former police Detective Sergeant who led covert investigations and was trained in surveillance to the standard the police require. He carries out most instructions personally, with hand-picked, trusted agents where a team is needed. Male and female operatives of varied backgrounds are available so a surveillance team can blend into any community.

That background shapes how we work: evidence is gathered to the standard a court expects, every instruction is tested for necessity and proportionality, and discretion is a habit rather than a promise. Everything you tell us stays between us, and that obligation does not end when your case does.

We are a Full Member of the Association of British Investigators, ICO registered with UK GDPR training completed, DBS checked, and covered by professional indemnity and public liability insurance. We are rated Excellent on Google and currently ranked number one in Sheffield by ThreeBestRated. The principal is also a Certificated Enforcement Agent, which is why we can handle commercial rent arrears recovery, lease forfeitures and traveller evictions in-house rather than passing them to a third party.

We are based in Sheffield and cover Yorkshire, Greater Manchester, Derbyshire and Nottinghamshire directly, with national reach through our network of agents. The office is open seven days a week, 8am to 9pm, and investigation hours are round the clock.

If you want to understand how investigations really work before you pick up the phone, Nathan talks through the job on the Diary of a Private Investigator podcast, on Apple Podcasts and Amazon Music.

If you are weighing up whether to hire a private investigator, the quickest way to get a straight answer is to ask. Call 0114 438 7077 or request a free, no-obligation consultation. We will tell you what can be done, what it will cost, and whether it is worth doing. Everything you tell us is confidential.

Frequently asked questions