How many members are in the House of Commons of the United Kingdom of Great Britain and Northern Ireland?

The House of Commons of the United Kingdom of Great Britain and Northern Ireland (The House of Commons or the Commons) is an elected body consisting of 650 members known as members of Parliament (MPs). The members are elected to represent constituencies by the first-past-the-post system and hold their seats until Parliament is dissolved.

The House of Commons of England started to evolve in the 13th and 14th centuries. It 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 has now assumed its current title.

The UK government is solely responsible for the House of Commons and its 650 members. The prime minister stays in office only as long as he or she retains the confidence of a majority of the Commons. It is the job of the members to represent the interests and concerns of the people of the UK in the House of Commons. The members have to consider and propose new laws and can scrutinise government policies by asking questions about current issues either in the Commons Chamber or in Committees.