3.4". Request asked what this means. 

Information provided "Retained by Department under Section 3.4" in the Catalogue means that the record has been kept by the responsible government department or agency under section 3(4) of the Public Records Act 1958 (rather than transferred to The National Archives). There is a copy of the Act on The National Archives Website at http://www.nationalarchives.gov.uk/policy/act/act.htm A government department may wish to retain a record after it is 30 years old for several reasons, the two most common reasons being (1) the record is still required by the department for administrative use or (2) the presence in the record of sensitive material. In such a case the department must apply for the Lord Chancellor's approval, and the application is scrutinised by the Advisory Council on National Records and Archives in the United Kingdom. If retention is approved, the record is shown in the Catalogue as 'Retained by Department under Section 3.4'. This part of the Public Records Act was not repealed or altered by Freedom of Information legislation. However, you have the right under FOI legislation to request access to the record