Two days later I received a response, which included the following:
"The ICO have stated that a public authority is entitled to treat as invalid a request where the real name of the applicant has not been used. Your request appears to have been made by “The Raven”. The ICO have stated that use of the phrase “the name of the applicant” in section 8 (1) (b) indicates that the real name of the applicant should be used when requesting information and not any other name, for example, a pseudonym. When a public authority receives a request from a person using an obvious pseudonym, there is no obligation to comply with the request, therefore the Cabinet Office will not be taking your request any further."
I went and checked this guidance, and sure enough:
This guidance is new; the end of the document says it was published on January 9th 2009. I have certainly obtained information via anonymous requests in the past, and yet all of a sudden there's a new rule saying that's not allowed. Obviously nobody told this to the Health Protection Agency, whose FoI guidance still states:
"Under the laws that govern access to information, anyone can ask for any information. A request may come from a member of the public, a writer, pressure group, a member of staff or a solicitor. The person making the request is not required to tell you why they want it, what they want it for or who they are, so requests may also be anonymous. All requests must be treated equally regardless of who is making the request."
It is important to state at this stage that while the Information Commissioner's Office is technically independent, it is actually sponsored by the Ministry of Justice. Could it be that the government just got fed up with people using their law to ask pesky questions? This interpretation completely goes against the spirit of the law. By demanding to know who is wanting information, this can give the public body clues as to why they want it; something the FoI Act says we don't have to disclose.