From Tech Week Europe:
Freedom of Information requests submitted via Twitter should be treated like any other, says the Information Commissioner’s Office in its July newsletter.
As long as the requester’s real name is used then the request is valid and should be responded to within 20 days as required by the Freedom of Information Actm, the ICO has said. The real name does not necessarily need to be the twitter user name and can be included in the account’s profile, said the ICO newsletter.