loyalists has increased. Official use of flags There are various practices for the flying of flags by public bodies in Northern Ireland. The Flags Regulations (Northern Ireland) Order 2000 requires that the Union Flag be flown over specified government buildings including Parliament Buildings and state offices on specified "named days" (honouring, for example Queen Elizabeth II's official birthday). The regulations also provide that, on the occasion of a visit to a government building by the British Monarch, the Royal Standard shall be flown, and the Union Flag can be flown, and on state visits from other heads of state the Union Flag and the national flag of the country of the visitor can be flown. The regulations prohibit any flags being flown from the relevant buildings except as expressly permitted by the regulations. When flags representing the "Home Countries" of England, Northern Ireland, Scotland and Wales are flown at official ceremonies, Northern Ireland is sometimes represented by the Saint Patrick's Cross, for instance on the barge Gloriana during the 2012 Thames Diamond Jubilee Pageant. In May 2016 the Ulster Banner was flown from horseback during the Musical Ride of the Household Cavalry at the Queen's 90th birthday celebration at Windsor, alongside the flags of England, Scotland and Wales. Other regulations exist for other public bodies in Northern Ireland. Use of flags by the Police Service of Northern Ireland is governed by the Police Emblems and Flags Regulations (Northern Ireland) 2002, which provides that no flag shall be used by the service other than its own flag. Local authorities Legislation relating to flag flying does not apply to district council buildings, and district councils follow a range of practices varying from flying the Union Flag on a number of council buildings every day of the year as at Lisburn, to flying no flags on any building, flying only the council flag or flying flags on the designated days in the same way as government buildings. In 2004, Belfast City Council commissioned a study on the flying of the Union Flag which noted that the Ulster Banner was flown alongside it by three unionist-controlled district councils at that time: Ards, Carrickfergus and Castlereagh. These councils have since been replaced. Displaying flags In Northern Ireland, some members from each of the unionist and nationalist communities use flags to declare their political allegiances and to mark territory. Unionists and loyalists fly the Union Flag