Some of the more confusing (and arguably confused) aspects of the British Constitution are those relating to executive (or royal) prerogative. Those with an interest in such matters may be pleased to know that the Ministry of Justice has just published a Final Report on these powers. It will appear in the Library's collections, of course, but it's also online as a .pdf.
The report is full of fascinating detail, not least that the most comprehensive legal textbook on the matter is now 'nearly 200 years old' (Joseph Chitty, A Treatise on the Law of the Prerogatives of the Crown (1820)). As well as the right to declare war, and so on, future and current monarchs' prerogatives include the sole right to the "printing or licensing the printing of the Authorised Version of the Bible, the Book of Common Prayer, state papers and Acts of Parliament" and also various "powers connected with prepaid postage stamps".
The MoJ is also seeking comments by 8 Jan 2010: RoyalPrerogativeReview@justice.gsi.gov.uk