They say they have so much correspondence with the industry, and are apparently so incompetent at searching their own records, that they can't fulfil the request without being unduly burdened, and thus they are not required to comply with the Freedom of Information request.
The City of London, London's financial district, is an autonomous city within Metro London, governed by a Lord Mayor and council who are elected by the banks in the City, with the biggest banks getting the most votes. The City of London Police have taken on the role of publicly-funded copyright enforcers for the entertainment industry, engaging in questionable tactics like demanding that registrars terminate domains without any kind of court order; sending secret blacklists of "pirate" sites to ad brokers and demanding (without any court order) that the ad networks boycott them, and more.
Torrentfreak sent the City of London Police an FOI request for records of its correspondence with entertainment lobby groups about the Pirate Bay. The City Police turned them down, saying that searching its computers for these files would take more than 18 hours, so it didn't have to do anything. I've participated in discovery against the email records of a major oil company, and I have an appreciation for what's at stake here, and this is just silly. Their Exchange server or similar could recover and save all messages containing the phrase "piratebay" "pirate bay" or "tpb," that are sent to or from domains associated with the entertainment industry lobby groups, and dump them into a single file with just a few keystrokes.
The City of London Police may believe that this undoubtably voluminous correspondence contains lots of embarrassing material that they'd like to redact, and undoubtedly doing this would take a long time, but the FOI's exemption for unduly burdensome requests does not exist to help officials avoid embarrassment.
My suggestion to Torrentfreak is to break your FOI into subparts:
* Domains associated with the entertainment industry in the City's email records
* Oldest correspondence to or from those domains containing either "pirate bay" "piratebay" or "tpb"
* All emails from one year after that date from those domains, containing those strings
* Lather, rinse repeat
We'd happily help out by filing some of these FOI requests. I've just filed one for "Entertainment industry domains used to correspond with the City of London Police."
"In order to establish the existence of any correspondence of this kind it would be necessary to examine all mail systems, all call logs and all files/documents held by the force," the reply read.
"The cost of completing this work would exceed the limit prescribed by the Secretary of State in accordance with powers contained in Section 12 of the Freedom of Information Act. The limit is currently set at £450 and the hourly rate is set at £25."