Of every piece of evidence people ask investigators and lawyers about, CCTV is the one with the cruellest deadline. The footage that shows exactly what happened on a high street, in a shop, in a stairwell or a car park usually still exists on the day of the incident. It is gone a fortnight to a month later, not because anyone deleted it, but because the recorder quietly wrote over it. If you are going to ask for it, you need to understand the overwrite clock, because every request that goes out a week late is a request for footage that no longer exists.
How long systems actually keep footage
There is no single legal minimum retention period for private CCTV in the UK or most jurisdictions. Retention is set by whoever owns the recorder, and it is driven almost entirely by hard-drive size. The practical norms:
- Domestic doorbell cameras and consumer systems: commonly 7 to 30 days, with cloud plans sometimes as short as 3 to 10 days on the free tiers.
- Small shops and offices: typically 14 to 31 days, one month being the most common setting.
- Banks, casinos, airports and transport hubs: months, sometimes a year or more, because they are required or choose to hold it.
- Vehicle dashcams and neighbour cameras: often 1 to 14 days on a loop card, shorter if the card is small and the resolution is high.
The number that matters is not the sticker on the box but the drive size divided by the camera count and recording quality. A 2 TB recorder covering 16 cameras at full HD continuously holds roughly a week. The same drive covering two cameras holds a month. When you ask a premises “how long do you keep footage”, the honest answer from the manager is often a guess, and the only way to know is to ask the installer’s paperwork or check the system menu.
Send the preservation request before you argue about anything else
The mistake people make is treating the footage request as part of the later legal claim, sent after letters have gone back and forth. It is the first thing to do, within days. A preservation request, sometimes called a spoliation letter or a letter of notice, tells the operator that footage from a specific camera at a specific time may be needed for a claim or investigation and asks them to export and hold it beyond the normal overwrite period. Operators are not obliged to keep footage indefinitely, but once they are on written notice that it is evidence, deleting it becomes far riskier for them, and in litigation the deletion of notified evidence can be held against the party responsible.
The letter needs five things: the exact date and time window, with a margin of half an hour either side; the camera or location as precisely as you can name it; the reason it is evidence; a request for the native export, not a copy filmed on a phone; and a deadline of a few days, because the request itself is time-critical. Ask them to reply confirming they have secured it. If they say the system has already overwritten it, get that in writing too.
Ask for the native file
When a shop assistant plays footage back on a monitor and films it with a phone, the result is technically an exhibit but it is a weak one. Native exports from the recorder carry embedded metadata, the time and date stamp as recorded by the system, and the full frame. Phone copies crop the frame, blur detail like faces and number plates, and give the other side an easy argument that the footage is unreliable. Most modern recorders can export to a USB stick in a proprietary or standard format; some formats need the manufacturer’s viewer software, which the operator can download in minutes. Accept that overhead. A native file with a visible system timestamp beats a shaky phone video every single time.
One caution on timestamps: cheap systems drift, sometimes by minutes, and recorders are frequently left on the wrong time zone or the wrong DST setting after a power cut. Note the system’s displayed clock against a known reference when you collect the export, because a defendant will attack the timeline if the clock is out, and you want to be the one who documented the drift rather than the one surprised by it.
Who you actually have to ask
The shop is often not the camera owner. High street cameras belong to the shop; car park cameras usually belong to the car park operator; bus and rail CCTV belongs to the transport operator with their own request procedure and their own retention, often short; council cameras belong to the council, whose footage request routes are public and whose disclosure under data protection rules for crime is routine. If police attended, ask for the body camera and incident footage early, since those retention windows expire too.
Doing it yourself under data protection rules
If you are the subject of the footage, or the parent of a child who is, you have a stronger and simpler tool: a subject access request. An operator must provide footage of you, though they may blur or refuse to show identifiable third parties. Give the exact time, place and description of your appearance, since operators cannot search weeks of footage for “the person in the grey coat”. The same request can be made by lawyers on behalf of clients with the client’s written authority.
The summary
CCTV evidence dies on a schedule set by a hard drive, not by goodwill. Move in the first days, put the operator on written notice, ask for the native export with its metadata, and note the clock drift. The footage that settles an argument is usually captured on the day and unrecoverable by the end of the month. The requests that arrive after the overwrite window do not fail because the system was against you. They fail because nobody asked in time.
