In a previous role at a previous TOC, I worked on our CCTV desk.
The on-station footage was kept for 28days due to storage capacity, and 7days for on-train footage, again due to storage. Hard drives on board being much much smaller than available for the station CCTV which was all linked and live monitored via wifi. On-train was stand alone.
Should any footage, whether on-train or on-station be requested within those timeframes, we would download it, and burn it to a disc to be given to whoever requested it. We made it clear, however, that on-train footage was only guaranteed to be available for 5 days. Why is explained in my story below.
We would only accept requests from BTP, Network Rail and managers directly. Naturally, if a member of the public wished to obtain some footage, they had to contact customer relations/legal dept/station managers directly themselves in the first instance, who'd then raise a request with us.
We had a few complaints when a member of the public claimed an incident happened with a staff member on the train (which I cannot say did or didn't happen, but the nature of the incident and seemed unlikely, and none of the other passengers were willing to be a witness for her) so she demanded the CCTV so she could "show it to the press" - she requested on day 6, and we told the requesting manager that we couldn't assure them that the footage could be recovered. This is because although the footage on-board is saved for 7days, after day 5, you're at the mercy of the unit's cycle. No unit spends more than two days away from a depot where download facilities are available. So if it's requested on day 5, said unit will land at a depot on day 5 or day 6. Footage definitely available. On day 6, that's now lands on day 6 or day 7. There are, however a handful of diagrams where the day 6 arrival is post peak, is fuelled and then goes again and lands back at a depot on day 8. If the request is made by about 10am on day 6 then the footage can be recovered on these units. If not, chances are it won't be.
This is exactly what happened. The unit in question was on a day 6 post-peak fpx diagram and then scuttled off not to be seen again for two days. By which time, naturally, the footage had wiped itself. Hysterical passenger believed this was deliberately to stop her taking her "evidence" to the press and managed to find our number and call us directly, along with several of her friends and family, to give us abuse about the matter. With BTP involved anyway - as she had now contacted them for some reason, it was easy enough for them to deal with.
So, my point is, being kept for a certain length of timed doesn't always mean available for that length of time. Now, my question is, should it?