The Freedom of Information Act recognises that the proactive publication of information by public authorities is very much in the public interest. Indeed, it is preferable that public authorities voluntarily put information in the public domain where this is possible, rather than it only being available on request. Section 19 of the Act places a duty on public authorities to have a publication scheme.
A publication scheme sets out classes of information which a public authority intends to make available to the public as a matter of course. It specifies the manner in which the information is to be made available (usually either from the public authority's website or in hard copy on demand) and indicates whether a charge will be made for the information.
If information is available under a publication scheme, it is likely to be exempt from the individual right of access on request because it is already reasonably accessible to the applicant (section 21). If a request is received that asks for information which is available under a publication scheme, this will not require a detailed or formal response. In some cases, the response may be no more than to send the information under cover of a compliments slip.
Where a request is received for information which is not available through the scheme then, by contrast, a more formal and more detailed response is likely to be required. If you hold information that is not exempt from the Freedom of Information Act then you should consider whether it should be included in the scheme.