An All Party Parliamentary Group (APPG) is an ad-hoc parliamentary committee, and is less formal than other parliamentary committees, like Standing Committees or Select Committees. To be properly constituted APPGs must have at least 20 members from across the major political parties represented in the UK parliament and some members from both the House of Commons and House of Lords.

Some APPGs also contain non-parliamentarians as members, though this is not the case with the Genocide Prevention APPG.

APPGs are split into two groups, subject groups, like the Genocide Prevention APPG or country groups which hold meetings and release reports on a particular country or region. The number of APPGs in both categories can grow and fall according to the interests of parliamentarians at that time; though over recent years the number of subject and country APPGs in the UK Parliament has risen.

Generally though some APPGs have a large membership (the Genocide Prevention APPG has over 120 members) usually around a dozen or so Parliamentarians will attend any particular meeting. APPGs must hold at least two meetings per year.

APPGs will from time to time release reports, organise trips abroad, ask for written or oral evidence from bodies or individuals outside parliament or undertake other activities. By and large, as long as the activity is seen as parliamentary in nature the members and executive are free to undertake anything them deem to further the purpose of the group.

You can find more information on the role of APPGs, the different subject and country groups, and the executives of groups from the following page in the House of Commons website: http://www.publications.parliament.uk/pa/cm/cmparty/050729/memi01.htm