<P> The House of Commons of England evolved in the 13th and 14th centuries . It eventually became the House of Commons of Great Britain after the political union with Scotland in 1707, and assumed the title of "House of Commons of Great Britain and Ireland" after the political union with Ireland at the start of the 19th century . The "United Kingdom" referred to was the United Kingdom of Great Britain and Ireland from 1800, and became the United Kingdom of Great Britain and Northern Ireland after the independence of the Irish Free State in 1922 . Accordingly, the House of Commons assumed its current title . </P> <P> Under the Parliament Act 1911, the Lords' power to reject legislation was reduced to a delaying power . The Government is solely responsible to the House of Commons and the Prime Minister stays in office only as long as he or she retains the support of a majority of the Commons . </P> <P> Although it does not formally elect the prime minister, the position of the parties in the House of Commons is of overriding importance . By convention, the prime minister is answerable to, and must maintain the support of, the House of Commons . Thus, whenever the office of prime minister falls vacant, the Sovereign appoints the person who has the support of the House, or who is most likely to command the support of the House--normally the leader of the largest party in the Commons, while the leader of the second - largest party becomes the Leader of the Opposition . Since 1963, by convention, the prime minister is always a member of the House of Commons, rather than the House of Lords . </P> <P> The Commons may indicate its lack of support for the Government by rejecting a motion of confidence or by passing a motion of no confidence . Confidence and no confidence motions are phrased explicitly, for instance: "That this House has no confidence in Her Majesty's Government ." Many other motions were considered confidence issues, even though not explicitly phrased as such . In particular, important bills that form a part of the Government's agenda were formerly considered matters of confidence, as is the annual Budget . When a Government has lost the confidence of the House of Commons, the prime minister is obliged either to resign, making way for another MP who can command confidence, or to request the monarch to dissolve Parliament, thereby precipitating a general election . </P>

The second largest party in the house of commons is usually known by what name