This is the list of United Kingdom MPs by seniority, 2010–2015. The Members of Parliament (MPs) are ranked by the beginning of their terms in office, in the House of Commons. The constituencies and party affiliations listed reflect those during the 55th Parliament. Seats and party affiliations for other Parliaments will be different for certain members. This article describes the criteria for seniority in the House of Commons, as set out in Factsheet M3 (The Father of the House) issued by the House of Commons Information Office and revised in June 2010.