Close up of hands in handcuffs behind the back

Are Private Investigators Legal? What They Can and Cannot Do

The idea that private investigators are not legal is a common misperception. As with any business, private investigators must operate legally in order to stay in operation. So how do private investigators ensure that they operate within the law? And what should you look for to ensure that a private investigation agency or individual investigator is operating lawfully?

What can private investigators legally investigate?

There are several specific types of investigations which are legal for private investigators to perform:

Search for a missing person

This could be a lost loved one, or even someone who’s attempted to escape debt.

Finding proof of an affair

A private investigator may be commissioned to investigate whether a client’s partner or spouse is being unfaithful.

Woman sat alone in living room drinking hot drink

Conducting background checks

This service is sometimes requested by one party seeking to make a legal commitment to another, for example: a private company seeking knowledge about a potential new hire, or an individual who wants to know more about a potential life partner.

Child support investigations

A recently divorced parent may want to hire a private investigator to collect evidence on their ex-partner, as this could highlight that they are the better choice when it comes to custody.

Corporate investigations

Businesses have a vested interest in the actions of their employees and the whereabouts of their assets and may hire a private investigator if they suspect dishonest behaviour on the part of an employee which jeopardizes the company, its reputation or assets.

Insurance fraud

Insurance companies may hire a private investigator to gather evidence which helps the insurer to determine the legitimacy of a claim, or to build a case against a claimant which could be presented before the law courts.

What methods of investigation can private investigators not legally use?

Anything which breaches existing privacy laws

Private investigators cannot resort to illegality when accessing information about a third party. Intercepting and reading letters or obtaining information from sensitive personal records (such as medical files) is prohibited. This also extends to any form of hacking, wiretapping or other illegal means of monitoring which require a forced invasion of privacy.

Pile of legal documents relating to private investigators

Trespassing on private property

It is not legal for private investigators to trespass on private property. Even law enforcement agents need to obtain a warrant before they can search a person’s home or private land.

Arresting or aggressively apprehending a target

A private investigator cannot simply confront their assigned target and attempt to physically apprehend them without facing serious legal consequences. Unlike law enforcement, private investigators also have no legal right to handcuff or forcibly restrain anyone.

What legal methods of investigation can private investigators use?

Searching official records

For anyone determined enough to pour through them, public records offices can provide useful insights through a variety of sources, such as marriage licenses, hospital records or wills.

Searching private databases

Data collection can be a very lucrative business. Most people won’t be able to afford to pay for access to a private database, but if a private investigation company can fit it into their budget, then it becomes a very useful tool for finding evidence.

Woman on busy street being viewed by private detective


Observing a target in a public location and using a GPS device to track their vehicle or person, are both lawful methods of gathering intel on a person’s movements and behaviours, providing certain criteria is met by carrying out a data impact assessment prior to any instruction. As long as a private investigator doesn’t break stalking laws, they can collect all the evidence they need.

How can you tell if a private investigator is operating legally?

Any trustworthy private investigation company will place the law above everything else. If you hire a private investigator and they break any laws when conducting the investigation, you could also be held accountable before the law.

There are several ways to tell if a private investigator is operating legally or not. Before hiring anyone, do some research into your available options and check to see if they’re adhering to these regulations:

Regulation of Investigatory Powers Act 2016

The Act controls who has the power to use certain invasive methods of investigation, and for what purposes. Private investigators are not included among the list of bodies approved for use of such methods. A private investigator may be required to work under the supervision of a RIPA when conducting investigations on behalf of Local Authorities and Government. A RIPA will be used to detail and justify the lawful reasons for surveillance to take place. A RIPA will be reviewed and signed off by a judge before any investigation can commence.

General Data Protection Regulation 2018

GDPR regulates how personal data is handled by corporations and organisations. Those processing data (companies) have more responsibilities around protecting and securely retaining personal information. With private investigators regularly dealing with a variety of data, they must be careful to adhere to these regulations.

Private investigator looking through legal files on a laptop

Information Commissioner’s Office

The ICO acts against businesses which violate the public’s privacy rights. If a private investigations company is registered with the ICO, this can be a good indicator of their commitment to privacy and the protection of information.

Contacting a Private Investigator 

Our team of Private Investigators are available 24/7, 365 days per year and are dedicated to providing free and anonomouys advise to anyone in need. Get in touch today on 020 3929 3797 or send us an email on


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