Arrest

PACE powers

The act of depriving a person of their liberty, with legal authority, so that they may be dealt with. Under section 24 of PACE, a constable may arrest without a warrant any person who is about to commit, is committing, or has committed an offence, provided there are reasonable grounds to suspect that and that the arrest is necessary for one of the prescribed reasons.

In practice

A person is under arrest from the moment they are told they are being arrested or it becomes obvious that they are being restrained. The officer must inform the person that they are under arrest and why, as soon as practicable, even if the reason is obvious. The person must be cautioned. Failure to comply with these requirements does not automatically make an arrest unlawful but may affect the admissibility of evidence.

Related terms

Necessity criteria
Reasonable grounds
PACE
Caution

Last updated 24 September 2026