Custody clock

Work out the actual milestone times from a start time, rather than counting hours in your head under pressure — for police detention in England & Wales, police custody in Scotland (including the further 12 hours a constable can authorise under section 11), and detention under section 136 of the Mental Health Act in England & Wales, which is not an arrest.

When did this period begin?

For an arrest, normally your arrival at the police station (the “relevant time”), not the moment of arrest. For a section 136 detention, use when you arrived at the place of safety instead — see that section below.

JavaScript is off, so this tool cannot do the date arithmetic for you. Add the hours below to the time the relevant period began by hand.

England & Wales

24 hours — the default maximum without charge (Police and Criminal Evidence Act 1984, s.41(1)).
36 hours — a superintendent (or above) can authorise this for an indictable offence (Police and Criminal Evidence Act 1984, s.42(1)), and only while the first 24 hours are still running (Police and Criminal Evidence Act 1984, s.42(4)).
96 hours — beyond 36 hours needs a magistrates’ court warrant (Police and Criminal Evidence Act 1984, s.43(1) and (5)(a)), and detention can never run beyond 96 hours after the relevant time (Police and Criminal Evidence Act 1984, s.44(3)).

Scotland

12 hours — initial period of custody.
Extended period — a further 12 hours, if a fresh authorisation is given under s.11.

Section 136 Mental Health Act (England & Wales) — not an arrest

24 hours — the maximum period for assessment, from arrival at the place of safety.
Up to 12 more hours if the examining doctor authorises an extension.