What is the difference between arrest and detention?

Understanding the difference between arrest and detention is crucial if you have been in contact with the police in England or Wales. Many people assume the terms mean the same thing, but legally, they are very different. The distinction matters because each carries different police powers, different limits, and different rights for you as an individual.

When the police misuse those powers, act outside the law, or detain or arrest someone without proper justification, this may amount to unlawful police conduct. In such circumstances, you may be entitled to bring a civil claim for compensation. This article explains the difference between arrest and detention, your rights at each stage, and when police actions may cross the line into unlawful behaviour.

Understanding police powers under UK law

Police powers in England and Wales are primarily governed by the Police and Criminal Evidence Act 1984, commonly referred to as PACE, alongside its Codes of Practice and other legislation, such as the Criminal Justice and Public Order Act 1994 and the Human Rights Act 1998.

These laws are designed to strike a balance between:

Allowing police to investigate crime, and
Protecting the public from arbitrary or oppressive use of power.

The difference between arrest and detention sits at the heart of that balance.

Image of policewoman walking with an arrested person in handcuffs while their partner is waiting for them near a car

What is detention?

A detention is a broader term for being held in custody. Detention occurs when the police restrict your freedom of movement for a limited purpose, usually during an investigation. It refers to the state of being held, which can occur via arrest or through other police powers and for varying durations.

While an arrest can lead to detention, detentions don’t always mean you are under arrest, and they do not always lead to an arrest. Detention can occur for shorter periods, such as during a stop and search without a formal arrest, or under different powers, such as under mental health laws.

Common types of detention:

Detention can happen in several ways, including:

Stop and search under section 1 PACE.
Voluntary attendance at a police station (which may later become detention).
Detention at a police station following arrest.
Traffic stops or roadside questioning.
Being stopped in the street.

The key factor is this: you are not free to leave, even if the police say you are “not under arrest”.

A police officer making an arrest, standing outside his patrol car at night, emergency lights flashing. The criminal is a young man in his 20s, standing his his hands on his head as the officer searches him.

Stop and search detention

During a stop and search, the police may detain you briefly to search you for prohibited items such as drugs, weapons, or stolen property.

Your rights during stop and search

The police must have reasonable grounds (unless using specific terrorism powers or s.60 of the Criminal Justice and Public Order Act.

They must also explain:

Who they are.
The legal power they are using.
The reason for the search.
Keep the detention as short as possible.

If police stop and detain you without lawful grounds, this may amount to unlawful detention, even if it lasts only minutes.

What is an arrest?

An arrest is a specific legal power the police have to deprive someone of their liberty to investigate or prevent a crime from occurring. It is a much more serious use of police power.

Governed by laws in the Police and Criminal Evidence Act 1984 (PACE), police must have reasonable grounds to suspect someone of an offence and must prove the necessity to arrest. The arrest may then lead to a formal detention, usually at a police station.

The necessity test for arrest

The necessity test is often where police action becomes unlawful.

Police must show arrest was necessary to:

Prevent injury or damage.
Protect a vulnerable person.
Prevent disappearance.
Allow for a prompt and effective investigation.
Prevent obstruction of justice.
Obtain your personal details.

If the police could have achieved their aim without arrest, the arrest may be unlawful. Read in more detail about the police’s necessity to arrest in our blog.

Police officer puts handcuffs on a man standing next to a car.

Your rights when arrested

When arrested, you have certain legal protections, and the police must follow strict procedures in order to ensure the arrest is lawful and that you and your rights are protected.

When you have been arrested, the police must:

Tell you that you are under arrest.
Explain the grounds and reasons for the arrest.
Use reasonable force only if necessary.

Your rights include:

The right to remain silent
The right to free legal advice
The right to have someone informed of your arrest (unless the police have a power to withhold this information if it impacts the investigation)
The right to be treated humanely and lawfully

Failure to respect these rights may amount to police misconduct.

Detention at the police station

After an arrest, you may be detained at a police station for questioning. There are set time limits on how long the police can detain you for. If they detain you for longer without a lawful reason, this could amount class as false imprisonment or unlawful detention, and you could be entitled to compensation.

Time limits on detention include:

Initial detention limit: 24 hours.
Can be extended to 36 hours (serious offences).
Further extensions require judicial approval.

So, what is the difference between arrest and detention?

Understanding the difference between arrest and detention allows individuals to recognise when police may have acted unlawfully. An arrest is a specific action taken by police to take an individual into custody. Detention is the condition of being held, which can happen after an arrest or through other, often shorter, police powers. An officer must justify why they are arresting you (under PACE Code G), but they can detain you for a search, which is less formal but still requires them to have grounds to suspect you may be carrying an illegal item.

Man in handcuffs being interrogated by a police detective in an interrogation room

When does police conduct become unlawful?

Police may act unlawfully if they:

Arrest without reasonable suspicion
Fail the necessity test.
Detain someone longer than permitted.
Use excessive force.
Fail to explain reasons for detention or arrest.
Conduct a stop and search without lawful grounds.
Ignore custody time limits.
Breach human rights protections.

Even short periods of unlawful detention can give rise to a civil claim.

What are civil claims against the police?

If police act unlawfully, you may be entitled to compensation. This can be gained through a civil action against the police claim. You can make a claim against the police for a number of things, including:

While making a claim for compensation will not reverse what happened to you or any trauma you suffered as a result, it can help you move forward from the incident and cover any losses you may have suffered as a result. Compensation can be awarded for loss of liberty, emotional distress, physical injury, reputational damage and financial losses.

Claims are brought against the police force, not individual officers. If you want the individual officer to be investigated, you can try making a police complaint about the specific officer, which should be investigated by the police or the IPOC in the most extreme instances.

Suspected man in handcuffs tightly clasping his hands together while talking to a detective

Why seek the help of experienced police claim solicitors?

Police misconduct cases are complex. Forces often argue their actions were justified, even where clear breaches exist. It can be difficult for individuals to understand the specific regulations in place and aspects of the law that the police must follow to be able to argue their point effectively. This is where a specialist police claim solicitor can help.

Specialist solicitors in this area of law know how to effectively present and argue these cases to ensure the most successful outcome. They can:

Analyse body-worn camera footage
Examine custody records
Challenge police justifications
Secure compensation through settlement or court action

If you have suffered unlawful arrest or detention by police and are thinking of making a claim, you should get in touch with a specialist action against the police solicitor to assist.

Understanding what the difference between arrest and detention is is not just a legal technicality. It is often the difference between lawful policing and misconduct.

Police powers are not unlimited. When those powers are abused, you can seek justice. If you believe your rights were breached, taking legal advice promptly is essential.

HNK Solicitors can help with your actions against the police claim

HNK Solicitors specialise in civil actions against the police and have extensive experience holding police forces accountable for unlawful arrest and detention. We have helped many clients secure large sums of compensation after they were mistreated by the police, and we can help you do the same.

We offer free consultations and can take on claims on a no-win, no-fee basis, so it won’t cost you a penny upfront to start your claim. Get in touch with our team today to discuss the details of your claim and get advice on next steps. Call us on 0151 668 0814 or email enquiries@hnksolicitors.com. Alternatively, fill in one of our online claim forms and a member of our team will be in touch to find out more.