Command paper

A command paper is a document issued by the UK Government and presented to Parliament. 
White papers, green papers, treaties, government responses, draft bills, reports from Royal Commissions, reports from independent inquiries and various government organisations can be released as command papers, so called because they are presented to Parliament formally "By Her Majesty's Command".
Dissemination.
Command papers are:
Numbering.
Command papers are numbered. Since 1870 they have been prefixed with an abbreviation of "command" which has changed over time to allow for new sequences.