Wrongful arrest and false imprisonment
An arrest is only lawful where the officer has reasonable grounds for suspicion and the arrest is genuinely necessary, as set out under the Police and Criminal Evidence Act 1984. Where those conditions are not met, the arrest, and any detention that follows it, can give rise to a claim for wrongful arrest and false imprisonment, regardless of whether charges were ever brought.
Excessive force
Officers are entitled to use reasonable force, but no more than the situation genuinely requires. Where restraint, handling or the use of equipment goes beyond what was necessary, that can amount to an assault or battery, a separate claim from the legality of the arrest itself.
Where a prosecution was brought without reasonable or probable cause, and ended in the defendant's favour, a claim for malicious prosecution may be available. It is a demanding claim to prove, since genuine malice or a lack of honest belief in guilt has to be shown, not simply that the case was eventually dropped.
The complaint and the claim are different things
A complaint to the police, or a referral to the Independent Office for Police Conduct, is a separate process from a civil claim, and the two can run alongside each other. A complaint can secure an apology, disciplinary action or a formal finding, but only a civil claim results in compensation, and the standard of proof and the process are entirely different.
Timing and evidence
Claims for assault generally have to be brought within three years, while claims for false imprisonment generally have six, but body-worn video, custody records and CCTV are not kept indefinitely. The practical window for gathering strong evidence is often much shorter than the legal limitation period, which is why early advice matters even where there is no immediate deadline.