Skip to main content


How long are the police permitted to investigate an alleged crime? (updated 24.05.23)

This is a burning question for most of those unfortunate enough to be under investigation by the police on suspicion of having committed an offence. In most cases, you are unlikely to learn you are under investigation until you are contacted and requested to attend an interview under caution at a police station (often referred to as a ‘caution plus 3’ interview). Once the interview is concluded, what happens next?

Prior to 2017, the majority of interviews were conducted under arrest conditions at a police station and suspects would be released on bail often with conditions and sometimes for long periods of time. Bail imposes a legal obligation on its subject to present him or herself at a police station (or court) on a particular date and time. There was no restriction on the amount of time that suspects could be placed on police bail attached to which there were often conditions. In 2017, the circumstances in which an individual can be placed on police bail were limited and even where applicable, there are now time limits which are supervised by the Courts (see our separate blog on this issue). There have been subsequent revisions in legislation invoked in 2022 which cede some of the decision-making back to the police (see our separate blog on this issue).

Now, most suspects are ‘released under investigation’ so what are the rules in those circumstances? There are time limits on the investigation for certain offences which are dictated by the classification of the offence. Proceedings for offences which are classified as 'summary-only’ (those triable only in a Magistrates' Court) must be commenced within six months of the date of the offence (save where certain exceptions apply – for instance in domestic related cases of assault). Such offences include common assault, harassment and most driving offences. Effectively, this means the police must charge (or lay an information before a Magistrates’ Clerk) within six months of the date of the offence (section 127(1) Magistrates' Courts Act 1980).

For all other offences, there is no statutory time limit. So does this mean that the police have no time constraint on their investigations? The tentative answer to this question is ‘yes’, but where there is a delay to a prosecution and there is fault on the part of the police, which leads to prejudice then the proceedings may be subject to an application to stay for ‘abuse of process’ (see for example S (S.P.) [2006] EWCA 756). Moreover, the right to have a trial within a reasonable time is enshrined in Article 6 of the European Convention on Human Rights ('the right to a fair trial'). This is a complicated area of law and there are competing issues of public interest.


If you think that delay in a police investigation has caused prejudice to your case then you should contact our criminal defence solicitors for legal advice on 02071838950.


Legal Disclaimer

Articles are intended as an introduction to the topic and do not constitute legal advice.