Arrest without warrant

s.24Police and Criminal Evidence Act 1984

Lets a constable arrest anyone involved, or reasonably suspected of being involved, in any offence, but only where they reasonably believe arrest is necessary for one of the reasons in s.24(5).

Arrest without warrant · Police and Criminal Evidence Act 1984, s.24Card 11 / 59

When you can use it

s.24(1)The person is about to commit or is committing an offence, or the constable has reasonable grounds for suspecting either
s.24(2)The constable has reasonable grounds for suspecting an offence has been committed, and reasonable grounds for suspecting the person is guilty of it
s.24(3)An offence has been committed and the person is guilty of it, or the constable has reasonable grounds for suspecting they are
s.24(4)AND the constable has reasonable grounds for believing arrest is necessary for at least one s.24(5) reason
s.24(5)(a)–(b)To find out the person's name or address
s.24(5)(c)To prevent the person causing physical injury to themselves or another, suffering physical injury, causing loss of or damage to property, committing an offence against public decency, or causing an unlawful obstruction of the highway
s.24(5)(d)To protect a child or other vulnerable person from the person
s.24(5)(e)–(f)To allow the prompt and effective investigation of the offence or the person's conduct, or to stop a prosecution being hindered by the person disappearing

What it allows

Arrest without a warrant for any offence, summary or indictable.
Covers people about to offend, offending now, or suspected of having offended.
The person must then be taken to a police station as soon as practicable, unless released on street bail (s.30, s.30A).

Key definitions

Reasonable grounds for suspecting – the officer must actually suspect, and the suspicion must be one a reasonable person would share on the facts known to the officer. Information from a briefing can be enough (O’Hara v Chief Constable of the RUC 1997).
Reasonable grounds for believing (necessity) – the officer must honestly believe arrest is necessary, and that belief must be objectively reasonable. They need not rule out every alternative (Hayes v Chief Constable of Merseyside 2011; Code G Note 2C).
Name or address – applies where the officer does not know it and cannot readily find it out, or reasonably doubts the one given.
Public decency – s.24(6): only where members of the public going about their normal business cannot reasonably be expected to avoid the person.

Safeguards

Tell the person they are under arrest and the ground for it, as soon as practicable, even if obvious (s.28). Otherwise the arrest is unlawful.
Code G 2.2 and 3.3: explain both elements, the suspected offence and why arrest is necessary.
Caution on arrest unless impracticable or already given (Code G 3.4, Code C 10.4).
Record the offence, the necessity reason(s), the caution and anything said, at the time if practicable (Code G 4.1–4.2).
Code G 2.8: weigh the victim, the offence, the suspect and the needs of the investigation.

Good to know

Both elements are needed. An offence plus suspicion is not enough without necessity (Code G 2.1).
The s.24(5) reasons are exhaustive (Code G 2.7).
Voluntary attendance for interview, a report for summons or a penalty notice may make arrest unnecessary (Code G 2.4, Note 2F).
Non-constables arrest under s.24A, for indictable offences only. Search on arrest is under s.32.

Legislation: Police and Criminal Evidence Act 1984, s.24 (opens legislation.gov.uk in a new tab)
Who can use it: A constable
Last checked: 3 November 2026, against the current law on legislation.gov.uk

Arrest without warrant: questions people ask

When can the police use arrest without warrant?

1. The person is about to commit or is committing an offence, or the constable has reasonable grounds for suspecting either 2. The constable has reasonable grounds for suspecting an offence has been committed, and reasonable grounds for suspecting the person is guilty of it 3. An offence has been committed and the person is guilty of it, or the constable has reasonable grounds for suspecting they are 4. AND the constable has reasonable grounds for believing arrest is necessary for at least one s.24(5) reason 5. To find out the person's name or address 6. To prevent the person causing physical injury to themselves or another, suffering physical injury, causing loss of or damage to property, committing an offence against public decency, or causing an unlawful obstruction of the highway 7. To protect a child or other vulnerable person from the person 8. To allow the prompt and effective investigation of the offence or the person's conduct, or to stop a prosecution being hindered by the person disappearing

Who can use arrest without warrant?

A constable.

What law gives the power for arrest without warrant?

Police and Criminal Evidence Act 1984, s.24.

More powers of arrest

All powers of arrest