Crown copyright exists in copyright materials produced by officers or servants of the crown in the course of their duties. There are a wide variety of crown copyright materials where copyright is waived and these materials may be reproduced without permission.  The material should however be reproduced accurately, properly acknowledged and not used in a misleading context. Some of these materials are legislations, public records, government press notices, consultation documents etc. A full list of the categories of materials covered by the waiver is available at http://www.opsi.gov.uk/advice/crown-copyright/copyright-guidance/waiver-of-crown-copyright.  For all other material (for example, publication by ministers or civil servants in journals or in conference proceedings) an appropriate licence known as the ‘Click-Use’ licence should be obtained.  Further guidance on Crown copyright is available from http://www.opsi.gov.uk/advice/crown-copyright/copyright-guidance/index and details of the click-use licences at http://www.opsi.gov.uk/click-use/index.htm.