How the PACE detention clock works, and why it does not start at the arrest
The clock in Part IV of PACE does not start when somebody is arrested. Section 41(2) gives four different answers depending on how the person came to be detained, and every limit and every review hangs off whichever one applies. Here is how the relevant time, the extensions and the review timetable actually fit together.
Put the arrest and arrival times into CUSTODY. It works out the relevant time under s.41(2), then every limit and review that hangs off it, with the section printed beside each figure. It is a calculation and an aid to checking one; the custody record is the record, and nothing here is legal advice.
The clock does not start at the arrest
This is the thing that catches people, and it is the whole reason the calculation is worth doing carefully.
Section 41(2) of the Police and Criminal Evidence Act 1984 defines the relevant time, and it gives different answers depending on how the person came to be detained. The common case — arrested away from a police station and taken to one — starts the clock at the arrival at the first police station, not at the arrest. Someone who attends voluntarily and is then arrested starts it at the arrest. Someone arrested in one police area and wanted in another has their own rule, and so does a person who arrives in England or Wales having been arrested elsewhere.
Get the limb wrong and every limit and every review below it moves with it, by however long the journey took.
The limits that hang off it
| Limit | Section | From the relevant time |
|---|---|---|
| Detention without charge | s.41(1) | 24 hours |
| Extended by a superintendent | s.42 | 36 hours |
| Warrant of further detention | s.43 | up to 36 hours from the time the warrant states |
| Extension of that warrant | s.44 | subject to the ceiling below |
| Absolute ceiling | s.44(3) | 96 hours |
Two points that are easy to lose. A superintendent's extension is available only for an indictable offence and only where the investigation is being conducted diligently and expeditiously. And a warrant runs from the time it states under s.43(12)(a), not from when it was granted or from the relevant time — so the 96-hour ceiling can bite before the warrant expires, and the earlier of the two is the one that matters.
Time that does not count
Section 41(6) takes certain periods out of the reckoning — broadly, time when the person is elsewhere for a reason the Act recognises rather than in detention being investigated. Every limit above shifts by however long that comes to, which is why it has to be recorded as it happens rather than reconstructed afterwards.
Reviews are a different clock
The review requirements in section 40 run on their own timetable and are the thing most often missed, because they do not follow the detention limits.
- The first review is not later than six hours after detention was first authorised — which is not the relevant time, and is frequently a different moment.
- Every review after that is at intervals of not more than nine hours.
- The nine hours runs from the last review actually carried out, not from when it was due. A review taken late does not shorten the next interval, and a review taken early does not lengthen it.
That last point is where hand-kept timetables go wrong, and it is why the next review due is calculated here from what was recorded rather than from an idealised schedule.
Custody time limits are a different thing again
People conflate the detention clock with custody time limits, and they have almost nothing to do with each other. The detention clock is hours before charge under PACE. Custody time limits are the maximum periods of remand in custody before trial, under the Prosecution of Offences (Custody Time Limits) Regulations 1987, and they are counted in calendar days.
Calendar days is not a detail. Adding a day's worth of milliseconds lands at 23:00 the day before once the clocks go back, which for a limit measured in days is simply the wrong date. It is worked here by moving the date rather than by adding elapsed time.
What this is not
It is a calculator. It does not know your case, it does not know what was authorised or by whom unless you tell it, and it has no view on whether continued detention is necessary or proportionate. Detention under Schedule 8 to the Terrorism Act 2000 is a different regime entirely and is not covered.
The output is a sheet showing every figure with the section it comes from and the times it was derived from, so that somebody else can check the working. That is the useful thing: not the answer, but an answer that can be audited.
The short version
| The job | Here | Notes |
|---|---|---|
| Relevant time under all four limbs of s.41(2) | Yes | And it says which limb it used |
| The 24, 36 and 96 hour limits | Yes | With the section beside each |
| A warrant run from the time it states | Yes | And the ceiling where that bites first |
| Time that does not count under s.41(6) | Yes | Every limit shifts with it |
| Reviews from the last one carried out | Yes | Not from when it was due |
| Custody time limits in calendar days | Yes | Correct across a clock change |
| A sheet somebody else can check | Yes | Every figure with its derivation |
| Work with no connection | Yes | Nothing leaves the machine |
| Terrorism Act Schedule 8 detention | No | A different regime |
| Advise whether detention is justified | No | It does arithmetic on times you give it |
| Replace the custody record | No | The custody record is the record |
Why it matters that it stays on your machine
The times going in belong to a person in detention, alongside a custody record number and frequently a name. That is about as sensitive as personal data gets, and typing it into a website is a disclosure to that website whatever the answer turns out to be.
This is arithmetic on a handful of timestamps. It runs in the tab, it works in a custody suite with no signal, and nothing is sent anywhere.
Questions people ask about the PACE detention clock